A134938 Pentagonal numbers that are the sum of a nonzero pentagonal number and a nonzero square in at least one way.

5, 51, 117, 145, 247, 425, 651, 715, 852, 1001, 1247, 1717, 1820, 2147, 2501, 3015, 3151, 4187

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Module[{nn=100, pent}, pent=PolygonalNumber[5, Range[nn]]; Select[Flatten[ Outer[ Plus, pent, Range[Sqrt[Max[pent]]]^2]]//Union, IntegerQ[ (1+Sqrt[ 1+24#])/6]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 27 2020 *)

Crossrefs

Sequence in context: A333261 A117710 A064019 * A068540 A208997 A041043

Adjacent sequences: A134935 A134936 A134937 * A134939 A134940 A134941

Keyword

nonn

Author

Jonathan Vos Post, Jan 21 2008

Status

approved