cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A116893 Numbers k such that gcd(k!+1, k^k+1) > 1.

This page as a plain text file.
%I A116893 #22 Feb 19 2024 22:53:04
%S A116893 1,3,23,39,51,63,95,99,131,183,191,215,239,251,299,303,315,363,371,
%T A116893 411,419,431,443,495,543,575,659,683,711,743,755,791,831,891,911,935,
%U A116893 975,1019,1031,1055,1071,1143,1155,1191,1211,1223,1251,1275,1295,1355
%N A116893 Numbers k such that gcd(k!+1, k^k+1) > 1.
%C A116893 See A116892 for the corresponding values of the GCD. See also comments in A116891.
%H A116893 Nick Hobson, <a href="/A116893/b116893.txt">Table of n, a(n) for n = 1..10000</a> (first 1832 terms from Antti Karttunen)
%H A116893 Nick Hobson, <a href="/A116893/a116893.c.txt">C program</a>.
%e A116893 gcd(1!+1, 1^1+1) = 2, gcd(2!+1, 2^2+1) = 1 and gcd(3!+1, 3^3+1) = 7, so 1 and 3 are the first two terms of the sequence.
%t A116893 Select[Range[1500], (GCD[ #!+1, #^#+1] > 1)&]
%o A116893 (PARI) isok(n) = gcd(n! + 1, n^n + 1) != 1; \\ _Michel Marcus_, Jul 22 2018
%o A116893 (C) See Links section.
%Y A116893 Cf. A014566, A038507, A067658, A116891, A116892, A116894.
%K A116893 easy,nonn
%O A116893 1,2
%A A116893 _Giovanni Resta_, Mar 01 2006