A144589 Prime(n-th "prime nonprime").

2, 7, 19, 29, 53, 71, 97, 103, 137, 173, 193, 233, 263, 271, 311, 359, 409, 421, 463, 491, 503, 571, 607, 647, 701, 743, 757, 809, 821, 839, 971, 1009, 1049, 1061, 1151, 1181, 1231, 1283, 1303, 1367, 1429, 1451, 1543, 1553, 1579, 1601, 1699, 1831, 1873, 1879

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Formula

a(n) = prime(A144570(n)).

Maple

A141468 := proc(n) 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:
A144589 := proc(n) ithprime(A144570(n)) ; end proc:
seq(A144589(n), n=1..120) ;  # R. J. Mathar, May 01 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, prime(t(prime(n)))) \\ Altug Alkan, Oct 17 2015

Crossrefs

Cf. A000040, A144570.

Sequence in context: A259370 A103034 A038952 * A179002 A232667 A034794

Adjacent sequences: A144586 A144587 A144588 * A144590 A144591 A144592

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 07 2009, corrected Jan 12 2009

Extensions

Extended by R. J. Mathar, May 01 2010

Status

approved