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

1,1

Comments

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

Links

Table of n, a(n) for n=1..6.

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

Example

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

Crossrefs

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

Sequence in context: A261262 A308527 A268517 * A004927 A074350 A144124

Adjacent sequences: A228223 A228224 A228225 * A228227 A228228 A228229

Keyword

nonn,base,hard

Author

Eric W. Weisstein, Aug 17 2013

Extensions

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

Status

approved