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A370596
Numbers k such that A007814(k) is a prime number.
2
4, 8, 12, 20, 24, 28, 32, 36, 40, 44, 52, 56, 60, 68, 72, 76, 84, 88, 92, 96, 100, 104, 108, 116, 120, 124, 128, 132, 136, 140, 148, 152, 156, 160, 164, 168, 172, 180, 184, 188, 196, 200, 204, 212, 216, 220, 224, 228, 232, 236, 244, 248, 252, 260, 264, 268, 276
OFFSET
1,1
COMMENTS
Numbers whose binary representation has a prime number of trailing 0's.
a(n)-1 is the sequence of numbers whose binary representation has a prime number of trailing 1's.
Numbers of the form (2^(p+1))*k + 2^p = 2^p * (2*k + 1), where p is prime and k >= 0.
All the terms are divisible by 4.
The asymptotic density of this sequence is Sum_{p prime} 1/2^(p+1) = 0.20734125492555583012... = A051006 / 2.
LINKS
MATHEMATICA
Select[Range[300], PrimeQ[IntegerExponent[#, 2]] &]
PROG
(PARI) is(n) = isprime(valuation(n, 2));
CROSSREFS
Subsequences: A017113, A051062.
Sequence in context: A311651 A311652 A311653 * A171949 A217319 A133466
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Feb 23 2024
STATUS
approved