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A066807
Integers of the form (2^k+1)/k.
1
3, 3, 57, 4971027, 29850020237398251227313, 17503832475167772961878049926333027042428946479619, 58167804601757508792865761341330650726830745576152064464908846133090363
OFFSET
1,1
COMMENTS
a(n)=0 mod(3).
The next term (a(8)) has 152 digits and a(9) has 217 digits. - Harvey P. Dale, Oct 20 2014
MATHEMATICA
Select[Table[(2^n+1)/n, {n, 300}], IntegerQ] (* Harvey P. Dale, Oct 20 2014 *)
PROG
(PARI) lista(nn) = {for (n=1, nn, if (type(v = (2^n+1)/n) == "t_INT", print1(v, ", ")); ); } \\ Michel Marcus, Nov 20 2013
CROSSREFS
Cf. A006521.
Sequence in context: A290567 A339758 A100065 * A165497 A051752 A332786
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jan 19 2002
STATUS
approved