A373839 Numbers k such that k and A276150(k) are both multiples of 3, where A276150 is the digit sum in the primorial base.

0, 9, 18, 27, 33, 42, 51, 66, 75, 84, 90, 99, 108, 117, 123, 132, 141, 156, 165, 174, 180, 189, 198, 207, 213, 222, 231, 246, 255, 264, 270, 279, 288, 297, 303, 312, 321, 336, 345, 354, 360, 369, 378, 387, 393, 402, 411, 426, 435, 444, 450, 459, 468, 477, 483, 492, 501, 516, 525, 534, 540, 549, 558, 567, 573, 582

Offset: 1

Author

Antti Karttunen, Jun 19 2024

Keywords

• nonn
• base

Comments

If x and y are terms and if A329041(x,y) = 1 (i.e., when adding x and y together will not generate any carries in the primorial base), then x+y is also a term. This follows from the quasi-exponential nature of A276086 and because A373837 is a multiplicative semigroup. See also A373599.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..12000
• Index entries for sequences related to primorial base

Crossrefs

Intersection of A008585 and A373841.

Indices of multiples of 3 in A373833.

Cf. A276150, A329041, A373838 (characteristic function).

Cf. also A373599, A373837.

Programs

PARI

isA373839 = A373838;