A380485 Numbers congruent to {0, 1, 2, 3, 4, 5} mod 30.

0, 1, 2, 3, 4, 5, 30, 31, 32, 33, 34, 35, 60, 61, 62, 63, 64, 65, 90, 91, 92, 93, 94, 95, 120, 121, 122, 123, 124, 125, 150, 151, 152, 153, 154, 155, 180, 181, 182, 183, 184, 185, 210, 211, 212, 213, 214, 215, 240, 241, 242, 243, 244, 245, 270, 271, 272, 273, 274, 275, 300, 301, 302, 303, 304, 305, 330, 331, 332, 333

Offset: 1

Author

Antti Karttunen, Feb 03 2025

Keywords

• nonn
• easy

Comments

Numbers k for which A276086(k) is not a multiple of 5.

Odd bisection gives numbers that are congruent to {0, 2, 4} mod 30, thus when halved, congruent to {0, 1, 2} mod 15, thus terms of A267711, numbers k such that k mod 3 = k mod 5.

Links

• Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,-1).

Crossrefs

Cf. A276086, A380484 (characteristic function), A380486 (complement).

Cf. also A267711 (odd bisection halved).

Programs

Mathematica

Select[Range[0, 333], Mod[#, 30] < 6 &] (* Amiram Eldar, Feb 03 2025 *)

PARI

is_A380485(n) = !((n\6)%5);

PARI

is_A380485(n) = ((n%30)<6);

Formula

a(2*n-1) = 2*A267711(n).