0,3

Felix Fröhlich, Table of n, a(n) for n = 0..1000

The smallest prime whose decimal expansion starts with 10^6 = 1000000 is 100000037, so a(6) = 37.

(PARI) a(n) = my(k=1); while(!ispseudoprime(eval(Str(10^n, k))), k++); k

Similar to but different from A033873.

Sequence in context: A002205 A251734 A033873 * A135449 A060388 A081821

Adjacent sequences: A260877 A260878 A260879 * A260881 A260882 A260883

nonn,base

Felix Fröhlich, Aug 02 2015

approved