A241028 Numbers n such that prime(n)^2 - 2*n is not prime.

5, 7, 8, 9, 11, 12, 13, 14, 17, 18, 20, 21, 23, 25, 26, 27, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 62, 63, 64, 65, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Mathematica

Select[Range[100], !PrimeQ[Prime[#]^2 - 2 #] &]

Prog

(Magma) [n: n in [1..100] | not IsPrime(NthPrime(n)^2-2*n)];

Crossrefs

Cf. A173473.

Sequence in context: A111339 A273786 A255922 * A171097 A166460 A118742

Adjacent sequences: A241025 A241026 A241027 * A241029 A241030 A241031

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 15 2014

Status

approved