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

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
(C) See Links section in A116893.

Crossrefs

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

Sequence in context: A247883 A027458 A062632 * A201481 A054555 A072287

Adjacent sequences: A116889 A116890 A116891 * A116893 A116894 A116895

Keyword

easy,nonn

Author

Giovanni Resta, Mar 01 2006

Extensions

Entries checked by Robert G. Wilson v, Mar 09 2006

Status

approved