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A102210 Number of primes that are bitwise covered by n. 5
0, 1, 2, 0, 1, 1, 4, 0, 0, 1, 3, 0, 2, 1, 6, 0, 1, 1, 4, 0, 2, 1, 7, 0, 1, 1, 5, 0, 4, 1, 11, 0, 0, 1, 2, 0, 2, 1, 5, 0, 1, 1, 5, 0, 4, 1, 10, 0, 1, 1, 4, 0, 4, 1, 9, 0, 2, 1, 8, 0, 8, 1, 18, 0, 0, 1, 3, 0, 1, 1, 6, 0, 1, 1, 5, 0, 3, 1, 10, 0, 1, 1, 6, 0, 2, 1, 10, 0, 3, 1, 9, 0, 6, 1, 17, 0, 1, 1, 4, 0, 4, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Index entries for sequences related to binary expansion of n

FORMULA

a(A102211(n)) = 0; a(A102212(n)) = 1; a(A102213(n)) > 1.

a(2^k-1) = A007053(k) for k > 1. - Amiram Eldar, Jan 12 2020

EXAMPLE

n=21->10101 -> a(21) = #{00101=5,10001=17} = 2.

MATHEMATICA

a[n_] := Count[Range[n], _?(PrimeQ[#] && BitAnd[n, #] == # &)]; Array[a, 100] (* Amiram Eldar, Jan 12 2020 *)

PROG

(MAGMA) [#[p:p in PrimesUpTo(n)| p eq BitwiseAnd(n, p)] :n in [1..105] ]; // Marius A. Burtea, Jan 12 2020

CROSSREFS

Cf. A007053, A007088, A004676, A080099, A102211, A102212, A102213, A102550.

Sequence in context: A333158 A293135 A321376 * A124220 A221755 A110298

Adjacent sequences:  A102207 A102208 A102209 * A102211 A102212 A102213

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Dec 30 2004

STATUS

approved

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Last modified May 30 18:38 EDT 2020. Contains 334728 sequences. (Running on oeis4.)