A116892 - OEIS

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A116892

Values of gcd(k!+1, k^k+1), when greater than 1.

2, 7, 47, 79, 103, 127, 191, 199, 263, 367, 383, 431, 479, 503, 599, 607, 631, 727, 743, 823, 839, 863, 887, 991, 1087, 1151, 1319, 1367, 1423, 1487, 1511, 1583, 1663, 1783, 1823, 1871, 1951, 2039, 2063, 2111, 2143, 2287, 2311, 2383, 2423, 2447, 2503, 2551

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

OFFSET

1,1

COMMENTS

Apart from the initial term (2) and few exceptional values (A116894) this sequence seems to coincide with A067658. The values of k for which the terms of this sequence are obtained are in A116893.

LINKS

Nick Hobson, Table of n, a(n) for n = 1..10000 (first 1832 terms from Antti Karttunen)

EXAMPLE

gcd(1!+1,1^1+1) = 2 gives the first term;

gcd(3!+1,3^3+1) = gcd(7,28) = 7 gives the second, and so on.

MATHEMATICA

f[n_] := GCD[n! + 1, n^n + 1]; t = Array[f, 1295]; Rest@ Union@ t (* Robert G. Wilson v, Mar 09 2006 *)

PROG

(PARI) lista(nn) = for (n=1, nn, if ((g=gcd(n! + 1, n^n + 1)) != 1, print1(g, ", "))); \\ Michel Marcus, Jul 22 2018

CROSSREFS

Cf. A014566, A038507, A067658, A116891, A116893, A116894.

Sequence in context: A247883 A027458 A062632 * A201481 A054555 A072287