A391850 Numbers k such that 15*k = A048720(m, k) for some m, where A048720 is carryless base-2 multiplication.

0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 17, 20, 21, 24, 30, 31, 32, 33, 34, 40, 42, 48, 51, 60, 62, 63, 64, 65, 66, 68, 80, 84, 85, 96, 102, 120, 124, 126, 127, 128, 129, 130, 132, 136, 160, 168, 170, 192, 195, 204, 240, 248, 252, 254, 255, 256, 257, 258, 260, 264, 272, 273, 320, 336, 340, 341, 384, 387, 390, 408

Offset

1,3

Comments

If n is a term, then 2*n is also a term, and vice versa. See A391851 for the odd terms.

Links

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

Index entries for sequences defined by congruent products between domains N and GF(2)[X].

Index entries for sequences related to binary expansion of n.

Index entries for sequences related to carryless arithmetic.

Formula

{0 followed by k such that A280500(15*k, k) = m for some m > 0}.

Prog

(PARI) is_A391850(k) = (!k || (0==lift(Pol(binary(15*k)*Mod(1, 2)) % Pol(binary(k))*Mod(1, 2))));

Crossrefs

Cf. A048720, A280500.

Row 15 of A391925.

Subsequences: A048718 (m=15), A115801 (m=19, conjectured), A115774 (m=23), A115807 (m=27), A391851 (odd terms).

Cf. also A391585, A391740, A391742, A391744, A391846, A391850, A391852, A391854, A391856, A391858, A391860.

Sequence in context: A204580 A347831 A391848 * A331206 A295298 A003401

Adjacent sequences: A391847 A391848 A391849 * A391851 A391852 A391853

Keyword

nonn,base

Author

Antti Karttunen, Dec 21 2025

Status

approved