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A298270 Triangular numbers that for some k are also the sum of the first k composites. 0
0, 10, 78, 153, 946, 177310, 450775, 13595505, 150988753, 4478601403, 5409300078, 5589152128, 76060335351, 248156250265, 1793751529485, 176149383165876, 187718592284301, 233626949305596, 11362376565228270, 18886935830647605, 1943937379018997076 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

10 is a term because 10 = 1 + 2 + 3 + 4 = 4 + 6.

PROG

(PARI) lista(nn) = {my(s=0); forcomposite(n=0, nn, if(ispolygonal(s, 3), print1(s, ", ")); s += n; ); } \\ after Michel Marcus at A053767

CROSSREFS

Intersection of A000217 and A053767.

Cf. A066527, A154587, A294174.

Sequence in context: A127536 A016201 A080618 * A082136 A153596 A316595

Adjacent sequences:  A298267 A298268 A298269 * A298271 A298272 A298273

KEYWORD

nonn

AUTHOR

Altug Alkan, Feb 15 2018

STATUS

approved

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Last modified July 10 00:05 EDT 2020. Contains 335570 sequences. (Running on oeis4.)