The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A051156 a(n) = (2^p^2 - 1)/(2^p - 1) where p is the n-th prime. 8
 5, 73, 1082401, 4432676798593, 1298708349570020393652962442872833, 91355004067076339167413824240109498970069278721, 7588608256743087977590500540116743445925584618982806531428980886590618779326218241 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Note that a(n) = Phi(p,2^p) or a(n) = Phi(p^2,2), where Phi(m,x) is the m-th cyclotomic polynomial and p is the n-th prime. - Thomas Ordowski, Feb 18 2014 LINKS FORMULA a(n) = A070526(prime(n)), a(n) = A019320(prime(n)^2). - Thomas Ordowski, Feb 18 2014 MATHEMATICA Table[Cyclotomic[Prime[n]^2, 2], {n, 7}] (* Arkadiusz Wesolowski, May 13 2012 *) Table[(2^Prime[n]^2-1)/(2^Prime[n]-1), {n, 10}] (* Harvey P. Dale, Apr 06 2019 *) CROSSREFS Cf. A051154, A051155, A051157. Sequence in context: A012640 A128889 A131958 * A092826 A334258 A322446 Adjacent sequences:  A051153 A051154 A051155 * A051157 A051158 A051159 KEYWORD nonn,easy AUTHOR 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 September 20 10:17 EDT 2020. Contains 337264 sequences. (Running on oeis4.)