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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A047779 Abundant or perfect numbers n such that neither n-1 nor n+1 is a prime. 0
56, 120, 144, 160, 176, 186, 204, 208, 216, 220, 246, 260, 288, 300, 304, 320, 324, 340, 342, 364 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

Source

EXAMPLE

a(1) = 56 because 55 and 57 are composite and the sum of the divisors of 56 is 64 which is >= 56 and no integer < 56 has this property.

CROSSREFS

A023196 is a superset.

Sequence in context: A063347 A054891 A118161 * A044243 A044624 A157330

Adjacent sequences:  A047776 A047777 A047778 * A047780 A047781 A047782

KEYWORD

easy,nonn

AUTHOR

Tony Davie (ad(AT)dcs.st-and.ac.uk)

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 23:53 EST 2012. Contains 205689 sequences.