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A328523 a(n) = number of terms in A002182 that are of the form A002182(n)/p for some prime p|n. 1

%I #10 Feb 18 2020 10:58:14

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

%T 2,3,2,1,1,2,3,2,2,3,2,3,3,2,2,1,3,2,1,3,1,2,2,2,2,3,2,2,4,3,1,4,2,2,

%U 2,2,1,2,2,2,2,4,3,4,3,2,3,1,1,1,1,2,2,3

%N a(n) = number of terms in A002182 that are of the form A002182(n)/p for some prime p|n.

%C Conjecture: a(n) > 0 for n > 1. (This is false.)

%C It seems that a(815) = 0. - _M. F. Hasler_, Jan 08 2020

%o (PARI) apply( {a(n)=#[0|p<-factor(n=A2182[n])[,1], setsearch(A2182,n/p)]}, [1..99]) \\ Uses global var. A2182 which must be assigned to a vector of at least n elements of that sequence. - _M. F. Hasler_, Jan 08 2020

%Y Cf. A002182, A199337, A330737.

%Y Cf. A112778(n) = A001222(A002182(n)) (bigomega of HCN's).

%K nonn

%O 1,5

%A _David A. Corneth_, Jan 04 2020

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Last modified April 19 12:14 EDT 2024. Contains 371792 sequences. (Running on oeis4.)