A261469 a(n) = prime(n+3) mod prime(n).

1, 2, 3, 3, 8, 10, 12, 12, 14, 12, 12, 10, 12, 16, 14, 14, 12, 12, 12, 12, 16, 18, 18, 14, 10, 8, 10, 20, 22, 24, 12, 18, 14, 18, 14, 16, 16, 16, 14, 18, 14, 16, 8, 18, 26, 28, 18, 10, 12, 12, 18, 18, 22, 18, 14, 14, 12, 12, 16, 26, 28, 20, 10, 20, 24, 30, 18, 16, 12

Offset: 1

Author

Altug Alkan, Aug 20 2015

Keywords

• nonn
• easy
• less

Examples

			a(3) = 13 mod 5 = 3.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A031165.

Programs

Magma

[NthPrime(n+3) mod NthPrime(n): n in [1.. 70]]; // Vincenzo Librandi, Aug 20 2015

Mathematica

a[n_]:=PowerMod[Prime[n + 3], 1, Prime[n]]; Table[a[n], {n, 80}] (* Vincenzo Librandi, Aug 20 2015 *)
Mod[Last[#],First[#]]&/@Partition[Prime[Range[80]],4,1] (* Harvey P. Dale, Jun 23 2017 *)

PARI

first(m)=vector(m,i,prime(i+3)%prime(i)) \\ Anders Hellström, Aug 20 2015

Formula

a(n) = prime(n+3) mod prime(n).