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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. 0
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 (list; graph; refs; listen; history; text; internal format)
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

CROSSREFS

Cf. A001405, A048106.

Sequence in context: A060267 A214516 A238004 * A056673 A128442 A290633

Adjacent sequences:  A048241 A048242 A048243 * A048245 A048246 A048247

KEYWORD

sign

AUTHOR

Labos Elemer

STATUS

approved

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Last modified August 2 12:00 EDT 2021. Contains 346422 sequences. (Running on oeis4.)