A013635 a(n) = prevprime(n) + n.

5, 7, 8, 11, 12, 15, 16, 17, 18, 23, 24, 27, 28, 29, 30, 35, 36, 39, 40, 41, 42, 47, 48, 49, 50, 51, 52, 59, 60, 63, 64, 65, 66, 67, 68, 75, 76, 77, 78, 83, 84, 87, 88, 89, 90, 95, 96, 97, 98, 99, 100, 107, 108, 109, 110, 111, 112, 119, 120, 123, 124, 125, 126

Offset: 3

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 3..5000

Crossrefs

Cf. A007917, A049711.

Programs

Magma

[n + PreviousPrime(n): n in [3..70]]; // Vincenzo Librandi, Mar 30 2019

Maple

[ seq(prevprime(i)+i,i=3..100) ];

Mathematica

Table[n+NextPrime[n,-1],{n,3,60}] (* Harvey P. Dale, Mar 29 2019 *)

PARI

a(n) = precprime(n-1) + n; \\ Michel Marcus, Mar 30 2019