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A295305 a(n) = tau(sigma(n)) - tau(n), where tau is the number of divisors (A000005) and sigma is the sum of divisors of n (A000203). 3
0, 0, 1, -1, 2, 2, 2, 0, -1, 2, 4, 0, 2, 4, 4, -3, 4, -2, 4, 2, 2, 5, 6, 4, -1, 4, 4, 2, 6, 4, 4, 0, 6, 4, 6, -5, 2, 8, 4, 4, 6, 4, 4, 6, 2, 8, 8, -4, 1, -2, 8, 0, 6, 8, 8, 8, 6, 8, 10, 4, 2, 8, 2, -5, 8, 7, 4, 6, 8, 7, 10, -4, 2, 4, 0, 6, 8, 8, 8, -2, -2, 8, 10, 0, 8, 8, 12, 10, 10, 0, 6, 10, 4, 11, 12, 6, 4, 0, 6, -5, 6, 8, 6, 8, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

FORMULA

a(n) = A062068(n) - A000005(n).

PROG

(PARI) A295305(n) = (numdiv(sigma(n)) - numdiv(n));

CROSSREFS

Cf. A000005, A000203, A062068, A295306.

Cf. A037197 (positions of zeros), A073803 (of positive terms), A073804 (of negative terms).

Sequence in context: A300075 A056557 A302986 * A082900 A171958 A301735

Adjacent sequences:  A295302 A295303 A295304 * A295306 A295307 A295308

KEYWORD

sign

AUTHOR

Antti Karttunen, Nov 21 2017

STATUS

approved

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Last modified March 20 05:34 EDT 2019. Contains 321344 sequences. (Running on oeis4.)