A086096 Semiprimes with a semiprime number of 1's in their binary representation.

15, 39, 46, 51, 57, 58, 77, 85, 86, 95, 106, 111, 119, 123, 141, 142, 159, 166, 169, 177, 178, 183, 187, 201, 202, 209, 215, 219, 221, 226, 235, 237, 249, 267, 278, 287, 291, 298, 303, 305, 323, 326, 329, 335, 365, 371, 377, 393, 394, 407, 411, 413, 417, 427

Offset

1,1

Links

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

Example

The sixth semiprime = 15 = '1111' with four 1's, so 15 is a term.

Mathematica

binWt[n_] := DigitCount[n, 2, 1]; seqQ[n_] := PrimeOmega[n] == 2 && PrimeOmega[binWt[n]] == 2; Select[Range[500], seqQ] (* Amiram Eldar, Dec 14 2019 *)

Crossrefs

Cf. A001358, A000120, A086097.

Sequence in context: A039605 A032654 A320721 * A272189 A336560 A176257

Adjacent sequences: A086093 A086094 A086095 * A086097 A086098 A086099

Keyword

nonn,base

Author

Jason Earls, Jul 09 2003

Status

approved