%I #9 Apr 27 2020 17:35:46
%S 5,51,117,145,247,425,651,715,852,1001,1247,1717,1820,2147,2501,3015,
%T 3151,4187
%N Pentagonal numbers that are the sum of a nonzero pentagonal number and a nonzero square in at least one way.
%H Harvey P. Dale, <a href="/A134938/b134938.txt">Table of n, a(n) for n = 1..1000</a>
%t 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 *)
%K nonn
%O 1,1
%A _Jonathan Vos Post_, Jan 21 2008
