|
Search: id:A098594
|
|
|
| A098594 |
|
Numbers n such that n!-1 and n!+1 are both semiprime. |
|
+0
1
|
| |
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
This sequence is formed of all those terms that appear in both A078778 and A078781.
No more terms < 307. - David Wasserman (dwasserm(AT)earthlink.net), Feb 26 2008
|
|
EXAMPLE
|
10!+1 = 3628801 = 11*329891 and 10!-1 = 3628799 = 29*125131 so 10 is a member of the sequence.
|
|
MAPLE
|
out:=[]: for n from 1 to 60 do: a:=n!-1: b:=n!+1: if (bigomega(a)=2) and (bigomega(b)=2) then out:=[op(out), n]: print(n): fi: od: out;
|
|
CROSSREFS
|
Cf. A078778, A078781.
Sequence in context: A022160 A022158 A032717 this_sequence A022799 A164682 A157482
Adjacent sequences: A098591 A098592 A098593 this_sequence A098595 A098596 A098597
|
|
KEYWORD
|
hard,more,nonn
|
|
AUTHOR
|
Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 17 2004
|
|
|
Search completed in 0.002 seconds
|
