A139370 - OEIS

A139370

Let the binary expansion of n be n = Sum_{k} 2^{r_k}, let e(n) be the number of r_k's that are even, o(n) the number that are odd; sequence lists n such that e(n) < o(n).

2, 8, 10, 11, 14, 26, 32, 34, 35, 38, 40, 41, 42, 43, 44, 46, 47, 50, 56, 58, 59, 62, 74, 98, 104, 106, 107, 110, 122, 128, 130, 131, 134, 136, 137, 138, 139, 140, 142, 143, 146, 152, 154, 155, 158, 160, 161, 162, 163, 164, 166, 167, 168, 169, 170, 171

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OFFSET

1,1

COMMENTS

e(n)+o(n) = A000120(n), the binary weight of n. For e(n) = o(n) see A039004.

Primes of this sequence are in A065049; but A065049 contains also other primes (see A152715). [Vladimir Shevelev, Dec 11 2008]

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

aQ[n_] := Module[{d = Reverse[IntegerDigits[n, 2]]}, Total@d[[1;; -1;; 2]] < Total@d[[2;; -1;; 2]]]; Select[Range[180], aQ] (* Amiram Eldar, Dec 15 2018 *)

PROG

See link in A139351 for Fortran program.

(PARI) isok(n) = {my(irb = Vec(select(x->(x%2), Vecrev(binary(n)), 1))); #select(x->(x%2), irb) < #irb/2; } \\ Michel Marcus, Dec 15 2018

CROSSREFS

Cf. A000120, A139351, A139352, A139353, A139354, A139355.

Cf. A039004, A139371, A139372, A139373.

Sequence in context: A053372 A088155 A005876 * A101532 A032708 A282094

Adjacent sequences: A139367 A139368 A139369 * A139371 A139372 A139373

KEYWORD

nonn

AUTHOR

Nadia Heninger and N. J. A. Sloane, Jun 07 2008

STATUS

approved