A391851 Odd numbers k such that 15*k = A048720(m, k) for some m, where A048720 is carryless base-2 multiplication.

1, 3, 5, 15, 17, 21, 31, 33, 51, 63, 65, 85, 127, 129, 195, 255, 257, 273, 341, 387, 511, 513, 529, 545, 645, 771, 819, 1023, 1025, 1041, 1057, 1089, 1285, 1365, 1539, 2047, 2049, 2065, 2081, 2113, 2177, 2565, 2581, 2693, 3075, 3123, 3267, 3855, 4095, 4097, 4113, 4129, 4161, 4225, 4353, 4369, 5125, 5141, 5381, 5461

Offset

1,2

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

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

Prog

(PARI) is_A391851(k) = ((k%2) && (0==lift(Pol(binary(15*k)*Mod(1, 2)) % Pol(binary(k))*Mod(1, 2))));

Crossrefs

Row 15 of A391725. Odd terms of A391850.

Cf. A048720, A280500.

Cf. also A391584, A391741, A391743, A391745, A391847, A391849.

Sequence in context: A103127 A103192 A391849 * A097856 A071593 A192794

Adjacent sequences: A391848 A391849 A391850 * A391852 A391853 A391854

Keyword

nonn,base

Author

Antti Karttunen, Dec 21 2025

Status

approved