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

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Last modified May 30 03:33 EDT 2017. Contains 287305 sequences.