A081102 - OEIS

A081102

Numbers k such that the first k digits of log_10(2) after the decimal point are primes.

1, 64, 1126, 1653, 13680, 27453

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

EXAMPLE

1 is listed because 3 is prime but 5 is not listed because 30102 is not prime.

MATHEMATICA

Do[ If[ PrimeQ[ FromDigits[ RealDigits[ N[ Log[10, 2], n + 10], 10, n] [ [1] ] ] ], Print[n] ], {n, 1, 10000} ]

CROSSREFS

KEYWORD

nonn,base,more

AUTHOR

John Sillcox (JMS21187(AT)aol.com), Apr 15 2003

EXTENSIONS

Offset corrected and a(5)-a(6) added by Amiram Eldar, Jan 27 2021

STATUS

approved