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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A122118 Least prime factor of 2^n+5^n. 0
2, 7, 29, 7, 641, 7, 29, 7, 17, 7, 29, 7, 641, 7, 29, 7, 97, 7, 29, 7, 641, 7, 29, 7, 17, 7, 29, 7, 641, 7, 29, 7, 193, 7, 29, 7, 73, 7, 29, 7, 17, 7, 29, 7, 641, 7, 29, 7, 97, 7, 29, 7, 641, 7, 29, 7, 17, 7, 29, 7, 641, 7, 29, 7, 274568286337, 7, 29, 7, 137, 7, 29, 7, 17, 7, 29, 7, 457 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

a(n_odd)=7, a(n=2+4k,k=0,1,...)=29, a(64)=274568286337 is unusially large. Cf. A074600 2^n + 5^n, A094475 Primes of form 2^n+5^n.

CROSSREFS

Cf. A074600, A094475.

Sequence in context: A013011 A013181 A191478 * A059803 A076043 A180448

Adjacent sequences:  A122115 A122116 A122117 * A122119 A122120 A122121

KEYWORD

nonn

AUTHOR

Zak Seidov (zakseidov(AT)yahoo.com), Oct 19 2006

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 14 16:29 EST 2012. Contains 205635 sequences.