A336854 - OEIS

%I #8 Aug 09 2020 00:33:09

%S 0,1,2,7,3,18,5,34,22,26,6,96,8,42,46,142,9,163,11,137,74,50,14,420,

%T 45,66,172,219,15,324,18,547,88,74,106,811,20,90,116,596,21,516,23,

%U 260,401,114,26,1662,115,327,130,342,29,1188,126,948,158,122,30,1578,33,146,639,2005,166,612,35,383,200,732,36,3430

%N a(n) = A336841(n)/2.

%H Antti Karttunen, <a href="/A336854/b336854.txt">Table of n, a(n) for n = 1..16384</a>

%H Antti Karttunen, <a href="/A336854/a336854.txt">Data supplement: n, a(n) computed for n = 1..65537</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%F a(n) = Sum_{d|n} (A048673(n)-A048673(d)).

%o (PARI)

%o A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

%o A336854(n) = { my(s=A003961(n)); sumdiv(s,d,(s-d))/2; };

%Y Cf. A003961, A003973, A048673, A336840, A336841.

%K nonn

%O 1,3

%A _Antti Karttunen_, Aug 08 2020