A104138 Smallest prime followed by n or more composites.

2, 3, 7, 7, 23, 23, 89, 89, 113, 113, 113, 113, 113, 113, 523, 523, 523, 523, 887, 887, 1129, 1129, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 1327, 9551, 9551, 15683, 15683, 15683, 15683, 15683, 15683, 15683, 15683, 19609

Offset: 0

Author

Lekraj Beedassy, Mar 07 2005

Keywords

• nonn

Comments

Except for a(1), records occur at even values of n, and each term appears an even number of times consecutively. (Proof. A maximal run of composites must begin and end at even numbers.) - Jonathan Sondow, May 31 2014

Examples

			a(10)=113 because it is the first prime occurring before primes 199,211,293,317,467,509,... all followed by at least ten successive composites.
		

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A002386, A005250, A030296, A053695.

Formula

Record prime A002386(n+1) appears A053695(n-1) times, for n>1.

a(n) = A030296(n) - 1, for n > 0. - Jonathan Sondow, May 31 2014

Extensions

a(34) corrected by Charles R Greathouse IV, Aug 09 2011