A168152 a(n) = prime(prime(n)) - prime(n).

1, 2, 6, 10, 20, 28, 42, 48, 60, 80, 96, 120, 138, 148, 164, 188, 218, 222, 264, 282, 294, 322, 348, 372, 412, 446, 460, 480, 490, 504, 582, 608, 636, 658, 710, 726, 762, 804, 824, 858, 884, 906, 962, 978, 1004, 1018, 1086, 1186, 1206, 1218, 1238, 1260, 1282

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 19 2009

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A006450.

Programs

Magma

[NthPrime(NthPrime(n))-NthPrime(n): n in [1..60]]; // Vincenzo Librandi, Jul 15 2016

Maple

A168152 := proc(n) local p; p := ithprime(n) ; ithprime(p)-p ; end proc: seq(A168152(n),n=1..120) ; # R. J. Mathar, Nov 19 2009

Mathematica

Table[Prime[Prime[n]] - Prime[n], {n, 1, 100}] (* G. C. Greubel, Jul 14 2016 *)
Prime[#]-#&/@Prime[Range[100]] (* Harvey P. Dale, Nov 16 2022 *)

PARI

a(n) = my(p=prime(n)); prime(p) - p; \\ Michel Marcus, Mar 08 2022

Formula

a(n) = A006450(n) - A000040(n).

a(n) ~ n (log n)^2. -Charles R Greathouse IV, May 25 2011

Extensions

a(10) corrected by R. J. Mathar, Nov 19 2009