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A331587
Odd numbers of the form k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).
3
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
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
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jan 21 2020
STATUS
approved