A359161 Numbers of the form 4u+1 with an even number of prime factors (counted with multiplicity).

1, 9, 21, 25, 33, 49, 57, 65, 69, 77, 81, 85, 93, 121, 129, 133, 141, 145, 161, 169, 177, 185, 189, 201, 205, 209, 213, 217, 221, 225, 237, 249, 253, 265, 289, 297, 301, 305, 309, 321, 329, 341, 361, 365, 377, 381, 393, 413, 417, 437, 441, 445, 453, 469, 473, 481, 485, 489, 493, 497, 501, 505, 513

Offset: 1

Author

Antti Karttunen, Dec 17 2022

Keywords

• nonn

Crossrefs

Intersection of A016813 and A028260.

Setwise difference A046337 \ A359163.

Setwise difference A016813 \ A359151.

Cf. A108181 (subsequence).

Cf. A359160 (characteristic function).

Programs

PARI

isA359161(n) = A359160(n);