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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A068780 Lesser of twin composite numbers. 10
8, 9, 14, 15, 20, 21, 24, 25, 26, 27, 32, 33, 34, 35, 38, 39, 44, 45, 48, 49, 50, 51, 54, 55, 56, 57, 62, 63, 64, 65, 68, 69, 74, 75, 76, 77, 80, 81, 84, 85, 86, 87, 90, 91, 92, 93, 94, 95, 98, 99, 104, 105, 110, 111, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Composites n such that n+1 is composite.

MATHEMATICA

Select[ Range[2, 200], !PrimeQ[ # ] && !PrimeQ[ # + 1] &]

CROSSREFS

Cf. A001359.

Equals A005381 - 1.

Sequence in context: A076769 A105741 A083134 * A174041 A096784 A175859

Adjacent sequences:  A068777 A068778 A068779 * A068781 A068782 A068783

KEYWORD

nonn,easy

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 04 2002

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 16:49 EST 2012. Contains 206058 sequences.