cp's OEIS Frontend

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.

A346239 Möbius transform of A341512, sigma(n)*A003961(n) - n*sigma(A003961(n)).

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%I A346239 #13 Aug 26 2021 10:56:19
%S A346239 0,1,2,10,2,33,4,74,44,55,2,278,4,115,116,490,2,613,4,498,242,169,6,
%T A346239 1942,92,265,742,1046,2,1591,6,3086,344,355,330,4986,4,487,542,3570,2,
%U A346239 3347,4,1638,2326,737,6,12542,376,2121,716,2546,6,9869,388,7510,986,943,2,12894,6,1225,4872,18970,630,5353,4,3498,1492
%N A346239 Möbius transform of A341512, sigma(n)*A003961(n) - n*sigma(A003961(n)).
%H A346239 Antti Karttunen, <a href="/A346239/b346239.txt">Table of n, a(n) for n = 1..16384</a>
%H A346239 <a href="/index/Pri#gaps">Index entries for primes, gaps between</a>
%H A346239 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A346239 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A346239 a(n) = Sum_{d|n} A008683(n/d) * A341512(d).
%F A346239 a(n) = A341512(n) - A346240(n).
%F A346239 a(n) = A347125(n) - A347124(n). - _Antti Karttunen_, Aug 25 2021
%o A346239 (PARI)
%o A346239 A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
%o A346239 A341528(n) = (n*sigma(A003961(n)));
%o A346239 A341529(n) = (sigma(n)*A003961(n));
%o A346239 A341512(n) = (A341529(n)-A341528(n));
%o A346239 A346239(n) = sumdiv(n,d,moebius(n/d)*A341512(d));
%Y A346239 Cf. A000203, A003961, A008683, A341528, A341529, A341512, A346240, A347096, A347124, A347125.
%Y A346239 Cf. also the sequences A001359, A029710, A031924 that give the positions of 2's, 4's and 6's in this sequence, or at least subsets of such positions.
%K A346239 nonn
%O A346239 1,3
%A A346239 _Antti Karttunen_, Jul 13 2021