A031166 a(n) = prime(n+4) - prime(n).

9, 10, 12, 12, 12, 16, 14, 18, 18, 14, 16, 16, 18, 18, 20, 18, 14, 18, 16, 18, 24, 22, 20, 18, 12, 12, 24, 24, 28, 26, 22, 20, 20, 24, 18, 22, 22, 18, 24, 20, 18, 18, 20, 30, 30, 30, 22, 16, 14, 22, 24, 24, 28, 20, 20, 18, 14, 22, 30, 30, 30, 24, 24, 26, 34, 32, 22

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A001223, A031131, A031165, A031167, A031168, A031169, A031170, A031171, A031172.

Programs

Haskell

a031166_list = zipWith (-) (drop 4 a000040_list) a000040_list
a031166 n = a031166_list !! (n-1) -- Reinhard Zumkeller, Aug 23 2015

Magma

[NthPrime(n+4)-NthPrime(n): n in [1..100] ]; // Vincenzo Librandi, Apr 23 2011

Maple

A031166 := n -> ithprime(n+4)-ithprime(n);

Mathematica

a=4; t=Array[Prime,123]; Drop[t,a]-Drop[t,-a] (* Vladimir Joseph Stephan Orlovsky, Aug 13 2009 *)

PARI

A031166(n)=prime(n+4)-prime(n) \\ M. F. Hasler, Dec 03 2018

Formula

a(n) = A031131(n) + A031131(n+2) = A001223(n) + A031165(n+1) and obvious variants. - M. F. Hasler, Dec 03 2018

Extensions

Offset changed from 2 to 1, and a(1)=9 added, by Vincenzo Librandi, Apr 23 2011