login
A332987
Sums of two nonzero pentagonal numbers.
7
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
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
KEYWORD
nonn
AUTHOR
Olivier Gérard, Mar 05 2020
STATUS
approved