

A140515


Numbers n such that one of floor(10^n * Pi) or ceiling(10^n * Pi) is prime.


1



0, 1, 5, 11, 18, 37, 601, 1901, 2394, 3970, 5826, 16207
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OFFSET

1,3


LINKS

Table of n, a(n) for n=1..12.
Carlos B. Rivera F. Puzzle 50. Approximation to pi with primes, The Prime Puzzles and Problems Connection.
Eric Weisstein's World of Mathematics, Pi Digits


EXAMPLE

ceiling(10^11*Pi) = ceiling(314159265358.9...) = 314159265359 is prime, so 11 is in the sequence.


PROG

(PARI) isA140515(n)=isprime(bitor(floor(10^n*Pi), 1))


CROSSREFS

Sequence in context: A140697 A048253 A102174 * A056996 A102184 A290751
Adjacent sequences: A140512 A140513 A140514 * A140516 A140517 A140518


KEYWORD

nonn,base,more


AUTHOR

Marvin Ray Burns, Jul 01 2008, Jul 02 2008


STATUS

approved



