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 A336918 #11 Aug 17 2020 20:52:08 %S A336918 1,2,3,5,6,7,8,10,11,12,13,14,15,17,19,21,22,23,24,25,26,27,28,29,30, %T A336918 31,33,34,35,37,38,39,40,41,42,43,46,47,50,51,52,53,54,55,56,57,58,59, %U A336918 60,61,62,63,65,66,67,69,70,71,73,74,75,76,77,78,79,82,83,84,85,86,87,88,89,91,92,93,94,95,96,97,101 %N A336918 Numbers k such that A000005(k) divides A003973(k); numbers k for which A336839(k) = 1. %C A336918 Numbers k such that A003961(k) is in A003601. Numbers which become (or stay as) arithmetic numbers when all primes in their prime factorization are replaced by the next larger primes. %C A336918 Numbers k for which A003973(k) is equal to A000005(k)*A336838(k). %H A336918 Antti Karttunen, <a href="/A336918/b336918.txt">Table of n, a(n) for n = 1..10000</a> %H A336918 Wikipedia, <a href="http://en.wikipedia.org/wiki/Arithmetic_number">Arithmetic number</a> %H A336918 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %o A336918 (PARI) %o A336918 A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; %o A336918 isA336918(n) = !(sigma(A003961(n))%numdiv(n)); %Y A336918 Cf. A000005, A003601, A003961, A003973, A336838, A336930. %Y A336918 Positions of ones in A336839. %Y A336918 Cf. A336919 (complement). %K A336918 nonn %O A336918 1,2 %A A336918 _Antti Karttunen_, Aug 12 2020