login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117430 Integer k such that 5^n + k = A117429(n). 1

%I

%S 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,

%T 4,2,-3,17,9,-4,-8,-6,12,14,-2,-6,-8,-2,-6,24,-2,14,-6,-4,-18,-6,-3,

%U -6,16

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

%C 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.

%F 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}.

%e a(0) = 3 because 5^0 + 3 = 4 = A001358(1) and no semiprime is closer to 5^0.

%e a(1) = -1 because 5^1 - 1 = 4 = A001358(1) and no semiprime is closer to 5^1.

%e a(2) = 0 because 5^2 + 0 = 25 = A001358(9), no semiprime is closer to 5^2 [this is the only 0 element].

%e a(3) = -2 because 5^3 - 2 = 123 = 3 * 41 = A001358(42), no semiprime is closer.

%e a(4) = 1 because 5^4 + 1 = 626 = 2 * 313, no semiprime is closer.

%e a(5) = 2 because 5^5 + 2 = 3127 = 53 * 59, no semiprime is closer.

%Y Cf. A000079, A001358, A117387, A117405, A117406, A117416, A117429.

%K easy,sign,less

%O 0,1

%A _Jonathan Vos Post_, Mar 14 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 11 21:15 EST 2017. Contains 295919 sequences.