A370664 Numbers k such that A176972(k) = 7^k + 7*k + 1 is prime.
0, 5, 11, 1389, 5351, 6207, 31173
Offset: 1
Programs
-
PARI
is(n) = ispseudoprime(7^n+7*n+1)
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.
is(n) = ispseudoprime(7^n+7*n+1)
[7^n + 7*n: n in [0..30]];
I:=[1, 14, 63]; [n le 3 select I[n] else 9*Self(n-1)-15*Self(n-2)+7*Self(n-3): n in [1..30]];
Table[(7^n + 7 n), {n, 0, 30}] (* or *) CoefficientList[Series[(1 + 5 x - 48 x^2)/((1 - x)^2 (1 - 7 x)), {x, 0, 30}], x]
a(n)=7^n+7*n \\ Charles R Greathouse IV, Apr 18 2013
Array begins: 2, 2, 2, 2, 2, 2, ... 1, 3, 5, 7, 9, 11, ... 1, 4, 9, 16, 25, 36, ... 1, 5, 15, 37, 77, 141, ... 1, 6, 25, 94, 273, 646, ... 1, 7, 43, 259, 1045, 3151, ... 1, 8, 77, 748, 4121, 15656, ... ...
A[0,0]=2; A[n_,k_]:=k^n+k*n+1;Table[A[n-k,k],{n,0,10},{k,0,n}]//Flatten
Comments