A048244 - OEIS

A048244

A048106 is applied to A001405: the terms indicate whether more, equal or fewer unitary than non-unitary divisors of the central binomial coefficient exists.

1, 2, 2, 4, 4, 2, 4, 8, 4, -2, 16, 8, 8, 0, 8, 16, 32, 16, 32, 16, 32, 0, 64, 32, -16, -64, -160, -256, -128, -224, 64, 128, 0, -256, 256, -128, -128, -512, 512, -256, 512, 0, 512, 0, -2048, -2816, -256, -1408, -1408, -2560, -2560, -4096, -1024, -1792, 2048

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..55.

FORMULA

A048106[ A001405[ x ] ] or A034444[ A001405[ x ] ] - A048105[ A001405[ x ] ] gives the terms resp.

EXAMPLE

n=54, binomial(54,27) has 3840 divisors of which 1024 are unitary and 2816 are not. The difference is -1792, so a(54) = -1792.

PROG

(PARI) a048106(n) = (2^(1+omega(n)) - numdiv(n));

a(n) = a048106(binomial(n, n\2)); \\ Michel Marcus, May 14 2018