A391578 Numbers k for which A391573(k) < k.

7, 11, 13, 14, 22, 23, 26, 27, 28, 29, 31, 39, 43, 44, 46, 47, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 71, 75, 77, 78, 79, 83, 86, 87, 88, 89, 91, 92, 93, 94, 95, 99, 101, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 123, 124, 125, 126, 127, 135, 139, 141, 142

Offset

1,1

Comments

If n is present, then 2*n is also present, and vice versa.

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.

Prog

(PARI)
A048720(b, c) = fromdigits(Vec(Pol(binary(b))*Pol(binary(c)))%2, 2);
A391573(n) = { my(t); forstep(k=3, oo, 2, if(!((t=A048720(n, k))%k), return(t/k))); };
is_A391578(k) = (A391573(k) < k);

Crossrefs

Cf. A048720, A391573, A391579 (complement).

Cf. also A391580.

Sequence in context: A337459 A245178 A287161 * A051266 A370007 A172247

Adjacent sequences: A391575 A391576 A391577 * A391579 A391580 A391581

Keyword

nonn,base

Author

Antti Karttunen, Dec 17 2025

Status

approved