A391855 - OEIS

A391855

Odd numbers k such that 19*k = A048720(m, k) for some m, where A048720 is carryless base-2 multiplication.

1, 3, 5, 7, 31, 33, 63, 65, 119, 127, 129, 133, 161, 195, 255, 257, 261, 321, 387, 455, 511, 513, 517, 641, 645, 771, 1023, 1025, 1029, 1057, 1281, 1285, 1539, 1799, 1823, 1911, 1991, 2047, 2049, 2053, 2081, 2113, 2561, 2565, 3075, 3591, 3647, 4039, 4095, 4097, 4101, 4129, 4161, 4225, 4229, 4257, 5121, 5125, 5153

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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(19*k, k) = m for some m > 0}.

PROG

(PARI) is_A391855(k) = ((k%2) && (0==lift(Pol(binary(19*k)*Mod(1, 2)) % Pol(binary(k))*Mod(1, 2))));