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 A358926 #11 Feb 16 2025 08:34:04
%S A358926 316,1625,456,3964051,21568,6561,346528,3588955448828761,1684992,
%T A358926 210804461608463437,36865024,835904150390625,2052407296
%N A358926 a(n) is the smallest centered n-gonal number with exactly n prime factors (counted with multiplicity).
%H A358926 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CenteredPolygonalNumber.html">Centered Polygonal Number</a>
%H A358926 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeFactor.html">Prime Factor</a>
%e A358926 a(3) = 316, because 316 is a centered triangular number with 3 prime factors (counted with multiplicity) {2, 2, 79} and this is the smallest such number.
%t A358926 c[n_, k_] := n*k*(k + 1)/2 + 1; a[n_] := Module[{k = 1, ck}, While[PrimeOmega[ck = c[n, k]] != n, k++]; ck]; Array[a, 7, 3] (* _Amiram Eldar_, Dec 09 2022 *)
%o A358926 (PARI) a(n) = if(n<3, return()); for(k=1, oo, my(t=((n*k*(k+1))/2+1)); if(bigomega(t) == n, return(t))); \\ _Daniel Suteu_, Dec 09 2022
%Y A358926 Cf. A001222, A358862, A358863, A358864, A358865, A358894, A358929.
%K A358926 nonn,more
%O A358926 3,1
%A A358926 _Ilya Gutkovskiy_, Dec 06 2022
%E A358926 a(10)-a(15) from _Daniel Suteu_, Dec 09 2022