A331587 Odd numbers of the form k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).

1, 9, 25, 49, 81, 143, 225, 289, 441, 475, 667, 729, 961, 1089, 1517, 1715, 2025, 2223, 2279, 2601, 2867, 3245, 3969, 4225, 5329, 5589, 6499, 6853, 7225, 7875, 8023, 8383, 8649, 9559, 9801, 9919, 10179, 11449, 11845, 11875, 13653, 14161, 16129, 16641, 19865

Offset

1,2

Comments

A192775 is a subsequence.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..8347

Example

The binary representations of 11 and of 13 are "1011" and "1101", respectively, so 11*13 = 143 belongs to the sequence.

Prog

(PARI) is(n) = if (n%2, fordiv (n, d, if (d*fromdigits(Vecrev(binary(d)), 2)==n, return (1)))); return (0)

Crossrefs

Cf. A030101, A092213, A192775, A331588, A331589.

Sequence in context: A110487 A259417 A030156 * A192775 A318737 A246331

Adjacent sequences: A331584 A331585 A331586 * A331588 A331589 A331590

Keyword

nonn,base

Author

Rémy Sigrist, Jan 21 2020

Status

approved