This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A333008 #19 Apr 22 2022 12:08:32 %S A333008 6,11,14,20,25,35,39,59,76,84,85,92,94,95,96,104,105,108,116,123,125, %T A333008 129,133,136,147,153,157,160,169,174,181,186,189,190,192,194,195,198, %U A333008 200,206,207,231,232,238,239,248,256,270,274,279,283,288,293,302,304,307,309,323,326,332,340,344,346,350,360,361,363,370,371,377,385,391,398,399 %N A333008 Square roots of perfect squares which are sum of two nonzero pentagonal numbers (A333007). %H A333008 Peter Kagey, <a href="/A333008/b333008.txt">Table of n, a(n) for n = 1..1000</a> %e A333008 a(7) = 39. a(7)^2 = 1521 = 1 + 1520. %t A333008 Take[Union[Select[Sqrt[#]&/@(Total/@Tuples[PolygonalNumber[ 5,Range[ 400]],2]),IntegerQ]],80] (* _Harvey P. Dale_, Apr 22 2022 *) %Y A333008 Cf. A333007 (squares), A333009 (successive differences). %Y A333008 Cf. A000326 (pentagonal numbers). %K A333008 nonn %O A333008 1,1 %A A333008 _Olivier Gérard_, Mar 05 2020