

A117190


Integer k such that 10^n + k = A115062(n).


1



1, 1, 1, 3, 7, 3, 3, 9, 7, 7, 19, 3, 11, 29, 27, 11, 61, 3, 3, 39, 11, 101, 9, 23, 7, 13, 67, 99, 209, 27, 11, 27, 21, 9, 193, 23, 67, 43, 59, 3, 17, 109, 63, 57, 31, 9, 33, 33, 33, 9, 57, 121, 231, 171, 31, 21, 3, 93, 149, 19, 7, 39, 83, 121, 51, 49, 49, 49, 99, 9, 33, 53, 39, 79, 47, 129, 133
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OFFSET

0,4


COMMENTS

For terms after the first several, 10^n + a(n) is only known to be a highly probable prime. If, for m>0, 10^n  m and 10^n + m are both nearest primes to 10^n, a(n) = m. For example, a(17) = 3 as 10^173 and 10^17+3 are the nearest primes to 10^17. Similarly, a(45) = 9 with both 10^459 and 10^45+9 prime.


LINKS

Table of n, a(n) for n=0..76.


FORMULA

a(n) = A115062(n)  10^n.


EXAMPLE

a(4) = 7 as 10^4 + 7 = 10007 = A115062(4), the nearest prime to 10^4.


MAPLE

a:= n> (t>((p, q)>`if`(qt<tp, q, p)t)(`if`(t=1, 1,
prevprime(t)), nextprime(t)))(10^n):
seq(a(n), n=0..80); # Alois P. Heinz, Aug 13 2014


CROSSREFS

Cf. A115062.
Sequence in context: A242461 A065443 A198350 * A113584 A111383 A195769
Adjacent sequences: A117187 A117188 A117189 * A117191 A117192 A117193


KEYWORD

sign


AUTHOR

Rick L. Shepherd, Mar 02 2006


STATUS

approved



