A144570 Nonprime(prime(n)).

1, 4, 8, 10, 16, 20, 25, 27, 33, 40, 44, 51, 56, 58, 64, 72, 80, 82, 90, 94, 96, 105, 111, 118, 126, 132, 134, 140, 142, 146, 164, 169, 176, 178, 190, 194, 202, 208, 213, 219, 226, 230, 243, 245, 249, 252, 266, 282, 287, 289, 294, 300, 302, 315, 322, 328, 335

Offset

1,2

Comments

The nonprimes A141468 at prime indices. - Juri-Stepan Gerasimov, Jul 22 2011

Links

Table of n, a(n) for n=1..57.

Formula

a(n) = A141468(A000040(n)).

Example

a(1) = nonprime(prime(1)) = nonprime(2) = 1,
a(2) = nonprime(prime(2)) = nonprime(3) = 4,
a(3) = nonprime(prime(3)) = nonprime(5) = 8, etc.

Maple

A141468 := proc(n) option remember ; if n <= 2 then n-1 ; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do: end if; end proc: A144570 := proc(n) A141468(ithprime(n)) ; end proc: seq(A144570(n), n=1..100) ; # R. J. Mathar, Mar 18 2010

Prog

(PARI) c(n) = {for(k=0, primepi(n), isprime(n++)&&k--); n};
t(n) = if(n<3, n-1, c(n-2));
vector(100, n, t(prime(n))) \\ Altug Alkan, Oct 17 2015

Crossrefs

Cf. A000040, A141468.

Sequence in context: A082934 A311003 A311004 * A036311 A020209 A311005

Adjacent sequences: A144567 A144568 A144569 * A144571 A144572 A144573

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 07 2009

Status

approved