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A062754 a(n) = gcd(n, sigma(n+1)). 1
1, 2, 1, 2, 1, 2, 1, 1, 9, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 4, 3, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 16, 3, 2, 7, 2, 1, 2, 3, 2, 1, 2, 1, 2, 9, 2, 1, 3, 1, 2, 1, 2, 1, 18, 5, 8, 3, 2, 1, 2, 1, 2, 1, 4, 1, 2, 1, 4, 3, 2, 1, 2, 1, 2, 5, 4, 7, 2, 1, 1, 9, 2, 1, 12, 1, 2, 3, 2, 1, 2, 7, 4, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

Table[GCD[n, DivisorSigma[1, n+1]], {n, 110}] (* Harvey P. Dale, May 25 2015 *)

PROG

(PARI) j=[]; for(n=1, 200, j=concat(j, gcd(n, sigma(n+1)))); j

(PARI) a(n) = gcd(n, sigma(n+1)); \\ Michel Marcus, Dec 16 2017

CROSSREFS

Cf. A000203, A009194.

Sequence in context: A069349 A167404 A280223 * A045888 A107279 A078461

Adjacent sequences:  A062751 A062752 A062753 * A062755 A062756 A062757

KEYWORD

nonn

AUTHOR

Jason Earls, Jul 15 2001

STATUS

approved

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)