A295368 - OEIS

A295368

For any number n > 0 with s divisors, say d_1, d_2, ..., d_s such that d_1 = 1 < d_2 < ... < d_s = n, the binary representation of a(n) is (d_1 mod 2, d_2 mod 2, ..., d_s mod 2).

1, 2, 3, 4, 3, 10, 3, 8, 7, 10, 3, 40, 3, 10, 15, 16, 3, 42, 3, 36, 15, 10, 3, 160, 7, 10, 15, 36, 3, 178, 3, 32, 15, 10, 15, 328, 3, 10, 15, 144, 3, 170, 3, 36, 63, 10, 3, 640, 7, 42, 15, 36, 3, 170, 15, 144, 15, 10, 3, 2696, 3, 10, 63, 64, 15, 170, 3, 36, 15

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OFFSET

1,2

COMMENTS

This sequence encodes in binary the parity of the divisors of a number.

For any n > 0, the binary representation of a(n) corresponds to the n-th row of A247795.

For any n > 0, n and a(n) have the same parity.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Colored logarithmic scatterplot of the first 100000 terms (where the color is function of A000005(n))

FORMULA

a(2^k) = 2^k for any k >= 0.