A062754 a(n) = gcd(n, sigma(n+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

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 * A342846 A045888 A335885

Adjacent sequences: A062751 A062752 A062753 * A062755 A062756 A062757

Keyword

nonn

Author

Jason Earls, Jul 15 2001

Status

approved