A359161 - OEIS

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A359161

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

4

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..63.

PROG

(PARI) isA359161(n) = A359160(n);

CROSSREFS

Intersection of A016813 and A028260.

Setwise difference A046337 \ A359163.

Setwise difference A016813 \ A359151.

Cf. A108181 (subsequence).

Cf. A359160 (characteristic function).

Sequence in context: A091113 A188159 A272600 * A327862 A108181 A368696

Adjacent sequences: A359158 A359159 A359160 * A359162 A359163 A359164

KEYWORD

nonn

AUTHOR

Antti Karttunen, Dec 17 2022

STATUS

approved