Braingle: '1, 3, 6, 55, 66...' Brain Teaser

1, 3, 6, 55, 66...

Series teasers are where you try to complete the sequence of a series of letters, numbers or objects.

Puzzle ID:	#17988
Fun:	(2.2)
Difficulty:	(3.12)
Category:	Series
Submitted By:	fishmed

What are the next three numbers in this series?

1, 3, 6, 55, 66, 171, 595, 666, 3003, 5995, ?, ?, ?

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Comments

swordflame Dec 02, 2004	For those people who don't know what a triangular number is, http://mathworld.wolfram.com/TriangularNumber.html is a very nice introduction (helped me anyway).
Nicky101 Dec 07, 2004	Thanx, I'll go there
i_am_hated Apr 13, 2005	me too...eventually ^_^
Nicholle Apr 21, 2005	I still don't get it.
deadeye823 Apr 26, 2005	wow...the hardest teaser on the site
darthforman May 11, 2005	it IS the hardest...
KimOHara May 21, 2005	I got the triangular part right away, but couldn't get the other part... the EASY part, now that I know what it was!
lessthanjake789 Jun 01, 2005	i got the palindromic triangle part, but dont know how to figure out triangle numbers, and wasnt sitting there for a LONG LONG time doing them and checking for palindrom-icity (yes, i made that word up)
triskit Jun 02, 2005	i didnt get it
Question_Mark Jun 11, 2005	WOW! THAT IS HARD!
brianz Jun 11, 2005	I realized they were all triangular numbers but couldn't figure out the correlation between them. Nice teaser, I don't think it is so hard.
Llama-Llover Sep 22, 2005	Orangutans forced to watch Days Of Our Lives could have aced that one. Try and think of something harder next time.
hamburger Oct 02, 2005	I got the palindrome part, ( Didnt everyone ) But I didnt see the triangular part right away.This was very hard!
(user deleted) Oct 05, 2005	I learned triangular numbers in year 7 EASY
schatzy228 Oct 09, 2005	WOW!, needed 2nd cup of coffee and 40yrs of memory back to high school, but it finally came to me GREAT JOB
bamfan Oct 24, 2005	con grats on the hardest teaser p.s. did any one get it right
smarty_blondy Nov 07, 2005	Hardest one on site? I got this one right away as i knew half of them and so i got the pattern. Only had to do a bit of googling for the missing ones. I will admit it's brilliant though, good job!
mrbrainyboy Dec 06, 2005	don't get it...
trickyone Jan 02, 2006	I got tha palindrome part but only got the triangular number part after the hint
tolkienfan27 May 10, 2006
MalcolmReynolds Oct 12, 2006	Heh .. I was trying to work out a pattern before I realized they were palindromic. Lol................. 1,3,6,10,55,66,171 corresonds with 1,2,3,10,11,18... Okay, maybe it's 123, 123... 1+0=1... 1+1= 2... 1+8=.. damn. Didn't want to go down the line calculating.. so I googled palindromic triangular numbers
Dan141 Nov 14, 2006	Easy, just simple....Not its the hardest one here
javlad27 Jul 28, 2007	what's a triangular number?
javaguru Jan 08, 2009	Took longer to figure out what the next three palindromic triangular numbers were than it did to figure out the rule. Pretty nice teaser, but not terribly difficult.
Photon Mar 09, 2009	I don't understand why this one is rated so difficult?
krishnan Sep 01, 2010	Nice, fun teaser, got the answer as soon as I saw 55 and 66.