%I #11 Apr 06 2016 12:51:20
%S 2,19,29,43,47,53,71,79,89,97,103,113,131,137,149,151,163,167,173,193,
%T 199,223,227,229,233,251,257,263,271,293,307,311,317,337,347,349,359,
%U 379,383,389,397,409,421,439,443,449,457,463,479,487,491,503,523,541
%N Primes p(n) such that n is a second-order nonprime number.
%C The prime/nonprime compound sequence ABB. - _N. J. A. Sloane_, Apr 06 2016
%e Nonprime(4) = 8.
%e The 8th prime is 19, the second entry.
%p For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - _N. J. A. Sloane_, Mar 30 2016
%t nonPrime[n_Integer] := FixedPoint[n + PrimePi[ # ] &, n]; Prime /@ nonPrime /@ nonPrime /@ Range[54] (* _Robert G. Wilson v_, Feb 04 2005 *)
%o (PARI) \We perform nesting(s) with a loop. cips(n,m) = { local(x,y,z); for(x=1,n, z=x; for(y=1,m+1, z=composite(z); ); print1(prime(z)",") ) } composite(n) = \ The n-th composite number. 1 is defined as a composite number. { local(c,x); c=1; x=0; while(c <= n, x++; if(!isprime(x),c++); ); return(x) }
%Y Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.
%K nonn
%O 1,1
%A _Cino Hilliard_, Jan 31 2005
%E Edited by _Robert G. Wilson v_, Feb 04 2005