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A319184 Numbers that are sums of consecutive pentagonal numbers. 6
0, 1, 5, 6, 12, 17, 18, 22, 34, 35, 39, 40, 51, 57, 69, 70, 74, 75, 86, 92, 108, 117, 120, 121, 125, 126, 145, 156, 162, 176, 178, 190, 195, 196, 209, 210, 213, 247, 248, 262, 270, 279, 282, 287, 288, 321, 330, 354, 365, 376, 386, 387, 399, 404, 405, 424, 425, 438, 457, 475 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..60.

Eric Weisstein's World of Mathematics, Pentagonal Number

MATHEMATICA

anmax = 1000; nmax = Floor[Sqrt[2*anmax/3]] + 1; Select[Union[Flatten[Table[Sum[k*(3*k-1)/2, {k, i, j}], {i, 0, nmax}, {j, i, nmax}]]], # <= anmax &] (* Vaclav Kotesovec, Dec 21 2018 *)

CROSSREFS

Cf. A000326, A002411, A034705, A034706, A319185, A322636, A322637.

Sequence in context: A032707 A240756 A127306 * A231959 A168145 A276407

Adjacent sequences:  A319181 A319182 A319183 * A319185 A319186 A319187

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Dec 21 2018

STATUS

approved

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Last modified December 8 23:37 EST 2021. Contains 349596 sequences. (Running on oeis4.)