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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A055008 GCD[Phi[x],Sigma[x]]=1, Phi=A000010, Sigma=A000203. 3
1, 2, 4, 8, 9, 16, 25, 32, 36, 50, 64, 81, 100, 121, 128, 144, 225, 242, 256, 289, 324, 400, 484, 512, 529, 576, 578, 625, 729, 800, 841, 900, 1024, 1058, 1089, 1156, 1250, 1296, 1600, 1681, 1682, 1936, 2025, 2048, 2116, 2209, 2304, 2312, 2401, 2500, 2601 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

EXAMPLE

For x=484, Phi[484]=220=2.2.11.11, Sigma[484]=931=7.7.19, so GCD[220,931]=1. Powers of odd prime multiplied by a power of 2 are here.

CROSSREFS

A000010, A000203.

Sequence in context: A049439 A079931 A188915 * A204826 A046678 A046680

Adjacent sequences:  A055005 A055006 A055007 * A055009 A055010 A055011

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), May 31 2000

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 17 06:27 EST 2012. Contains 205998 sequences.