A373384 Numbers k that are multiples of 3 and also A059975(k) is a multiple of 3, where A059975 is fully additive with a(p) = p-1.

6, 15, 27, 33, 36, 42, 48, 51, 69, 78, 87, 90, 105, 114, 120, 123, 141, 159, 162, 177, 186, 189, 195, 198, 213, 216, 222, 225, 231, 249, 252, 258, 264, 267, 285, 288, 294, 300, 303, 306, 321, 336, 339, 351, 357, 366, 384, 393, 402, 405, 408, 411, 414, 429, 438, 447, 465, 468, 474, 483, 495, 501, 513, 519, 522, 537

Offset: 1

Author

Antti Karttunen, Jun 06 2024

Keywords

• nonn

Comments

A multiplicative semigroup: if m and n are in the sequence, then so is m*n.

Examples

			6 = 2*3 is present as A059975(6) = (2-1)+(3-1) = 1+2 = 3 is also a multiple of 3.
27 = 3*3*3 is present as A059975(27) = (3-1)+(3-1)+(3-1) = 2+2+2 = 6 is also a multiple of 3.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Positions of multiples of 3 in A373368.

Cf. A059975, A373383 (characteristic function).

Intersection of A008585 and A373385.

Programs

PARI

isA373384 = A373383;