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 A358932 #8 Feb 16 2025 08:34:04
%S A358932 19,85,31,469,253,2025,5995,4061,15742,48061,8191,220543,384766,
%T A358932 3080161,3272671,6192631,8385271,31453021,58159102,249495467,
%U A358932 401469279,268418041,134193151,2885548927,1610563582,8589393821,33280753395,83751780091,171658174447
%N A358932 a(n) is the smallest centered n-gonal number with binary weight n.
%H A358932 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CenteredPolygonalNumber.html">Centered Polygonal Number</a>
%H A358932 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%e A358932 31 is the smallest centered pentagonal number with binary weight 5 (31_10 = 11111_2), so a(5) = 31.
%t A358932 c[n_, k_] := n*k*(k + 1)/2 + 1; a[n_] := Module[{k = 1, ck}, While[DigitCount[ck = c[n, k], 2, 1] != n, k++]; ck]; Array[a, 25, 3] (* _Amiram Eldar_, Dec 09 2022 *)
%Y A358932 Cf. A000120, A358930, A358931.
%K A358932 nonn,base
%O A358932 3,1
%A A358932 _Ilya Gutkovskiy_, Dec 06 2022