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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A085753 Least k such that n^n + k is a semiprime. 3
3, 0, 6, 3, 2, 5, 6, 3, 4, 3, 6, 31, 6, 3, 4, 1, 20, 19, 28, 3, 8, 3, 60, 5, 16, 15, 46, 3, 2, 7, 12, 13, 4, 3, 18, 3, 9, 3, 32, 7, 6, 37, 30, 61, 2, 81, 26, 5, 34, 79, 62, 27, 44, 5, 16, 15, 10, 133, 12, 31, 28, 49, 26, 21, 92, 43, 76, 67, 38, 57, 36, 43, 24, 115, 2, 25, 74, 179, 28, 27 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The parity of a(n) is opposite to that of n.

LINKS

Dario Alejandro Alpern, Factorization using the Elliptic Curve Method

MATHEMATICA

PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{k = 0}, While[ PrimeFactorExponentsAdded[n^n + k] != 2, k++ ]; k]; Table[ f[n], {n, 1, 40}]

CROSSREFS

Cf. A089542, A089543, A089544.

Sequence in context: A113062 A005889 A095712 * A120008 A162197 A160770

Adjacent sequences:  A085750 A085751 A085752 * A085754 A085755 A085756

KEYWORD

nonn

AUTHOR

Jason Earls (zevi_35711(AT)yahoo.com), Jul 21 2003

EXTENSIONS

Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 14 2003

Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 22 2003

a(69)..a(80) and a(81)=52, a(82)=15 from Max Alekseyev (maxale(AT)gmail.com), Jun 13 2009

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

Content is available under The OEIS End-User License Agreement .

Last modified February 16 15:27 EST 2012. Contains 205930 sequences.