

A117430


Integer k such that 5^n + k = A117429(n).


1



3, 1, 0, 2, 1, 2, 2, 2, 2, 3, 2, 2, 2, 4, 4, 2, 8, 6, 2, 3, 2, 2, 4, 2, 6, 2, 4, 2, 3, 17, 9, 4, 8, 6, 12, 14, 2, 6, 8, 2, 6, 24, 2, 14, 6, 4, 18, 6, 3, 6, 16
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OFFSET

0,1


COMMENTS

Distance from 5^n to the nearest semiprime. See also: A117416 Semiprime nearest to 3^n. A117405 Semiprime nearest to 2^n. A117387 Prime nearest to 2^n.


LINKS

Table of n, a(n) for n=0..50.


FORMULA

a(n) = Integer k such that 5^n + k = A117429(n). a(n) = A117429(n)  5^n. a(n) = Min{k such that A001358(i) + k = 5^n}.


EXAMPLE

a(0) = 3 because 5^0 + 3 = 4 = A001358(1) and no semiprime is closer to 5^0.
a(1) = 1 because 5^1  1 = 4 = A001358(1) and no semiprime is closer to 5^1.
a(2) = 0 because 5^2 + 0 = 25 = A001358(9), no semiprime is closer to 5^2 [this is the only 0 element].
a(3) = 2 because 5^3  2 = 123 = 3 * 41 = A001358(42), no semiprime is closer.
a(4) = 1 because 5^4 + 1 = 626 = 2 * 313, no semiprime is closer.
a(5) = 2 because 5^5 + 2 = 3127 = 53 * 59, no semiprime is closer.


CROSSREFS

Cf. A000079, A001358, A117387, A117405, A117406, A117416, A117429.
Sequence in context: A128618 A284826 A101548 * A143676 A002726 A119734
Adjacent sequences: A117427 A117428 A117429 * A117431 A117432 A117433


KEYWORD

easy,sign,less


AUTHOR

Jonathan Vos Post, Mar 14 2006


STATUS

approved



