A323879 - OEIS

%I #6 Feb 08 2019 00:10:21

%S 0,1,0,1,0,2,0,1,0,1,0,3,0,1,0,1,0,2,0,1,0,1,0,4,0,1,0,1,0,3,0,1,0,1,

%T 0,3,0,1,0,1,0,2,0,2,0,1,0,4,0,1,0,1,0,2,0,1,0,1,0,5,0,1,0,1,0,2,0,1,

%U 0,2,0,5,0,1,0,1,0,2,0,1,0,1,0,3,0,1,0,2,0,4,0,1,0,1,0,4,0,1,0,1,0,2,0,1,0

%N Number of divisors d of n such that A276154(d) divides n.

%H Antti Karttunen, <a href="/A323879/b323879.txt">Table of n, a(n) for n = 1..30030</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%F a(n) = Sum_{d|n} [A276154(d)|n], where [ ] is the Iverson bracket.

%o (PARI)

%o A276151(n) = { my(s=1); forprime(p=2, , if(n%p, return(n-s), s *= p)); };

%o A276152(n) = { my(s=1); forprime(p=2, , if(n%p, return(s*p), s *= p)); };

%o A276154(n) = if(!n,n,(A276152(n) + A276154(A276151(n))));

%o A323879(n) = sumdiv(n,d,!(n%A276154(d)));

%Y Cf. A002110, A276154.

%Y Cf. also A323878.

%K nonn,base

%O 1,6

%A _Antti Karttunen_, Feb 07 2019