A102551 -id:A102551 - cp's OEIS frontend

A102550 Number of distinct prime-factors of n that are bitwise covered by n.

0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 2, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 2, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 2, 1, 1, 0, 1, 1, 0, 0, 0, 1, 2, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0

Offset: 1

Reinhard Zumkeller, Jan 14 2005

nonn

p is bitwise covered by n iff (p = (n AND p)) bitwise: A080099(n,p)=p.

Index entries for sequences related to binary expansion of n

Cf. A001221 (omega), A007088, A004676, A080099, A102210.

Cf. A102551, A102553, A102554, A102555.

a[1] = 0; a[k_] := Module[{f=FactorInteger[k][[;; , 1]]}, Count[BitAnd[k, f]-f, 0]];  Array[a,120] (* Amiram Eldar, Feb 06 2019 *)

a(A102553(n)) = A001221(A102553(n));
a(A102554(n)) < A001221(A102554(n));
a(A102551(n)) = 0, a(A102551(n)) > 0;
a(A102555(n)) = n;
a(m) < n for m < A102555(n).
a(n) = Sum_{p|n} (binomial(n,p) mod 2), where p is a prime. - Ridouane Oudra, May 03 2019

Offset 1 from Amiram Eldar, Feb 06 2019

cp's OEIS Frontend

A102550 Number of distinct prime-factors of n that are bitwise covered by n.

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