A093864 Consider the least k such that prime(k) > n*composite(k). Sequence gives prime(k).

11, 53, 173, 521, 1523, 4327, 11579, 31469, 85411, 229547, 614477, 1640461, 4393369, 11806297, 31656553, 84979847, 228346229, 614582509, 1654328267, 4457160931, 12016414601, 32419200013, 87508870037, 236325429049, 638490906857, 1725782162981, 4666340800001

Offset: 1

Author

Amarnath Murthy, Apr 19 2004

Keywords

• nonn

Comments

a(n) = prime(A073459(n)).

Examples

			a(2) = 53 as 53 > 2*26 where 53 and 26 are respectively the 16th prime and composite numbers.
		

Crossrefs

Cf. A002808, A000040, A073459, A125075.

Programs

PARI

nextcomposite(k)=if(k<3,4,if(isprime(k),k+1,k));

PARI

p=2;q=4;for(n=1,19, while(p<=n*q,p=nextprime(p+1);q=nextcomposite(q+1));print1(p,","));

Extensions

Terms a(4) to a(19) and PARI code from Klaus Brockhaus, Apr 26 2004

Terms a(20) to a(23) from Klaus Brockhaus, Nov 19 2006

More terms from David Wasserman, Apr 20 2007