The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A260982 a(n) = (2^(2^(n+1)) + 2^(2^n) + 1)/21. 0
 1, 13, 3133, 204525373, 878416384666881853, 16203922234330403022943873881213226813, 5513909011300771210646237381366090850171917477741023928710521838825947516733 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = A001576(2^n)/21. - Michel Marcus, Aug 14 2015 EXAMPLE a(2) = (2^(2^(2+1)) + 2^(2^2) + 1)/21 = 13. MATHEMATICA Table[(2^(2^(n + 1)) + 2^(2^n) + 1)/21, {n, 1, 10}] (* Vincenzo Librandi, Aug 08 2015 *) PROG (PARI) first(m)=my(v=vector(m, t, (2^(2^(t+1))+2^(2^t)+1)/21)); v; /* Anders Hellström, Aug 07 2015 */ (MAGMA) [(2^(2^(n+1)) + 2^(2^n) + 1)/21: n in [1..10]]; // Vincenzo Librandi, Aug 08 2015 CROSSREFS Cf. A001576 (1^n + 2^n + 4^n). Sequence in context: A208315 A296174 A220642 * A159357 A221885 A134159 Adjacent sequences:  A260979 A260980 A260981 * A260983 A260984 A260985 KEYWORD nonn,easy AUTHOR Marco Ripà, Aug 07 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 19 09:51 EST 2021. Contains 340269 sequences. (Running on oeis4.)