OFFSET
1,1
LINKS
Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
FORMULA
a(n) ~ 0.4n log n.
EXAMPLE
n=2: 21001 is prime.
n=69: 691001 is prime.
PROG
(Magma) [ n: n in [1..300] | IsPrime(Seqint([1, 0, 0, 1] cat Intseq(n))) ];
(PARI) is(n)=isprime(10000*n+1001) \\ Charles R Greathouse IV, Jun 06 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Parthasarathy Nambi, Apr 07 2005
STATUS
approved