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A342460 a(n) = 1 if n > 1 and is divisible by the sum of its prime factors (with repetition), otherwise 0. 1

%I #13 Mar 23 2021 16:16:56

%S 0,1,1,1,1,0,1,0,0,0,1,0,1,0,0,1,1,0,1,0,0,0,1,0,0,0,1,0,1,1,1,0,0,0,

%T 0,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,1,1,0,0,0,0,0,1,0,

%U 0,1,1,1,1,0,0,0,0,0,1,0,0,0,1,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1

%N a(n) = 1 if n > 1 and is divisible by the sum of its prime factors (with repetition), otherwise 0.

%C Characteristic function of A036844. a(n) - A010051(n) gives the characteristic function for A046346.

%H Antti Karttunen, <a href="/A342460/b342460.txt">Table of n, a(n) for n = 1..65537</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%F a(1) = 0; and for n > 1, a(n) = [0=A238525(n)], where [ ] is the Iverson bracket.

%t Array[Boole[Mod[#, Total@ Flatten[ConstantArray[#1, #2] & @@@ FactorInteger[#]]] == 0] - Boole[# == 1] &, 105] (* _Michael De Vlieger_, Mar 19 2021 *)

%o (PARI) A342460(n) = if(n<2,0,my(f=factor(n)); !(n%((f[, 1]~*f[, 2])))); \\ After code in A001414 and A036844.

%Y Cf. A001414, A010051, A036844, A046346, A238525.

%K nonn

%O 1

%A _Antti Karttunen_, Mar 18 2021

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Last modified July 16 18:33 EDT 2024. Contains 374358 sequences. (Running on oeis4.)