A033920 Largest proper substring of n-th prime that is prime (0 if none).

0, 0, 0, 0, 0, 3, 7, 0, 3, 2, 3, 7, 0, 3, 7, 5, 5, 0, 7, 7, 7, 7, 3, 0, 7, 0, 3, 7, 0, 13, 7, 31, 37, 13, 0, 5, 7, 3, 67, 73, 79, 0, 19, 19, 97, 19, 11, 23, 7, 29, 23, 23, 41, 5, 7, 3, 2, 71, 7, 2, 83, 29, 7, 31, 31, 31, 31, 37, 47, 3, 53, 59, 67, 73, 79, 83, 89, 97, 0, 0, 41, 2, 43, 43, 43

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base

Examples

			p(16)=53, largest prime substring is 5, so a(16)=5.
		

Crossrefs

See A033274 for the 'no prime substring' sequence.

Extensions

More terms from Patrick De Geest, Jun 15 1998