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 A062712 #14 Jul 01 2025 19:27:11
%S A062712 1,15,36,45,325,561,1225,1540,3025,4186,11781,40755,41041,58311,
%T A062712 121771,221445,1334161,1413721,1777555,3000025,5785101,27169506,
%U A062712 36855405,113123361,321197185,1167483681,1533776805,1631432881
%N A062712 Numbers that are n-gons for three or more n's, where n=3,4,5,...,16.
%D A062712 Albert H. Beiler, Recreations in the Theory of Numbers: The Queen of Mathematics Entertains 185-99 (2d ed. 1966)
%H A062712 Donovan Johnson, <a href="/A062712/b062712.txt">Table of n, a(n) for n = 1..58</a>
%H A062712 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PolygonalNumber.html">Polygonal Number</a>
%e A062712 45 is a triangular, hexagonal and hexadecagonal number
%t A062712 Select[Tally[Flatten[Table[PolygonalNumber[b,Range[10^6]],{b,3,16}]]],#[[2]]>2&][[;;,1]]//Union (* _Harvey P. Dale_, Aug 26 2023 *)
%K A062712 nonn
%O A062712 1,2
%A A062712 _Harvey P. Dale_, Jul 14 2001
%E A062712 More terms from _Eric W. Weisstein_, Nov 30 2003.