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 A271319 #14 Sep 24 2023 14:54:04
%S A271319 1,2,1,2,3,2,2,2,3,3,3,2,3,4,2,2,3,4,3,3,3,3,3,2,4,3,3,2,5,3,2,4,3,4,
%T A271319 3,2,4,4,4,3,4,3,3,3,3,4,3,2,4,4,4,2,4,4,3,4,3,3,4,4,3,5,2,3,4,4,4,4,
%U A271319 4,3,4,2,4,5,3,3,4,3,4,3,4,4,5,4,3,4
%N A271319 Number of distinct prime factors of the n-th n-gonal number (A060354).
%H A271319 Colin Barker, <a href="/A271319/b271319.txt">Table of n, a(n) for n = 2..1000</a>
%F A271319 a(n) = A001221(A060354(n)).
%e A271319 a(7) = 2 because A060354(7) = 112 = 2^4 * 7^1.
%t A271319 Table[PrimeNu[PolygonalNumber[n,n]],{n,2,90}] (* _Harvey P. Dale_, Sep 24 2023 *)
%o A271319 (PARI)
%o A271319 pg(m, n) = (n^2*(m-2)-n*(m-4))/2 \\ n-th m-gonal number
%o A271319 a(n) = omega(pg(n, n))
%o A271319 vector(100, n, n++; a(n))
%Y A271319 Cf. A001221, A060354, A271320, A271321, A271322.
%K A271319 nonn
%O A271319 2,2
%A A271319 _Colin Barker_, Apr 04 2016