A228226 Integer lengths of log(2)-primes: numbers n such that the concatenation of the first n decimal digits of log(2) is prime.

321, 466, 1271, 15690, 18872, 89973

Offset: 1

Author

Eric W. Weisstein, Aug 17 2013

Keywords

• nonn
• base
• hard

Comments

No others <= 90220 - Eric W. Weisstein, Oct 28 2015

Examples

			log(2) = 0.6931471805... and the 321-digit number 6931...0641 is the smallest prime in the first digits, so a(1) = 321
		

Links

• Eric Weisstein's World of Mathematics, Constant Primes
• Eric Weisstein's World of Mathematics, Integer Sequence Primes
• Eric Weisstein's World of Mathematics, Natural Logarithm of 2 Digits

Crossrefs

Cf. A002162 (decimal digits of log(2)).

Extensions

a(6) from Eric W. Weisstein, Oct 28 2015