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 A379930 #11 Jan 09 2025 19:17:32 %S A379930 1,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,113, %T A379930 121,169,199,211,223,227,229,233,277,289,311,331,337,361,433,443,449, %U A379930 499,529,557,577,599,661,677,733,773,811,841,877,881,883,887,911,961,977,991,997,1018,1027,1037,1041 %N A379930 Numbers that have the same number of divisors as there are runs in their base-10 representation. %C A379930 Numbers k such that A000005(k) = A043562(k). %H A379930 Robert Israel, <a href="/A379930/b379930.txt">Table of n, a(n) for n = 1..10000</a> %e A379930 a(5) = 23 is a term because it has two runs, 2 and 3, and two divisors, 1 and 23. %p A379930 filter:= proc(n) local L; L:= convert(n, base, 10); nops(L) - numboccur(0, L[2..-1]-L[1..-2]) = numtheory:-tau(n) end proc: %p A379930 select(filter, [$1..1000]); %t A379930 A379930Q[n_] := DivisorSigma[0, n] == Length[Split[IntegerDigits[n]]]; %t A379930 Select[Range[1000], A379930Q] (* _Paolo Xausa_, Jan 08 2025 *) %Y A379930 Cf. A000005, A043562, A379929, A379931. %K A379930 nonn,base %O A379930 1,2 %A A379930 _Robert Israel_, Jan 06 2025