A332987 Sums of two nonzero pentagonal numbers.

2, 6, 10, 13, 17, 23, 24, 27, 34, 36, 40, 44, 47, 52, 56, 57, 63, 70, 71, 73, 75, 82, 86, 92, 93, 97, 102, 104, 105, 114, 118, 121, 122, 127, 129, 139, 140, 143, 146, 150, 152, 157, 162, 167, 168, 177, 180, 181, 184, 187, 188, 196, 198, 209, 211, 215, 222, 227

Offset

1,1

Links

Peter Kagey, Table of n, a(n) for n = 1..10000

Mathematica

Module[{nn=15, pn}, pn=PolygonalNumber[5, Range[nn]]; Select[Union[ Total/@ Tuples[ pn, 2]], #<=Last[pn]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 15 2021 *)

Crossrefs

Cf. A000326 (pentagonal numbers).

Analogs are A000404 (square numbers), A051533 (triangular numbers), A286636 (centered square numbers), A287960 (centered triangular numbers), A288631 (square pyramidal numbers).

Sequence in context: A247785 A190701 A184918 * A023419 A183990 A049838

Adjacent sequences: A332984 A332985 A332986 * A332988 A332989 A332990

Keyword

nonn

Author

Olivier Gérard, Mar 05 2020

Status

approved