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A228226
Integer lengths of log(2)-primes: numbers n such that the concatenation of the first n decimal digits of log(2) is prime.
1
321, 466, 1271, 15690, 18872, 89973
OFFSET
1,1
COMMENTS
No others <= 90220 - Eric W. Weisstein, Oct 28 2015
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
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
KEYWORD
nonn,base,hard
AUTHOR
Eric W. Weisstein, Aug 17 2013
EXTENSIONS
a(6) from Eric W. Weisstein, Oct 28 2015
STATUS
approved