

A195463


a(n) = 4^(n+1) + 7.


1



11, 23, 71, 263, 1031, 4103, 16391, 65543, 262151, 1048583, 4194311, 16777223, 67108871, 268435463, 1073741831, 4294967303, 17179869191, 68719476743, 274877906951, 1099511627783, 4398046511111, 17592186044423, 70368744177671, 281474976710663
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OFFSET

0,1


COMMENTS

These are the even terms of A168415. Since the odd terms of A168415 are divisible by three the primes of this sequence are the same as A104066.


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5,4).


FORMULA

a(n) = 4^(n+1) + 7.
From Alexander R. Povolotsky, Sep 19 2011: (Start)
G.f.: (11  32*x)/(1  5*x + 4*x^2).
a(n+1) = 4*a(n)  21. (End)
a(n) = A188165(2n+2)  2.  Bruno Berselli, Sep 26 2011


PROG

(PARI) a(n)=4^(n+1)+7 \\ Charles R Greathouse IV, Sep 19 2011
(MAGMA) [4^(n+1) + 7: n in [0..30]]; // Vincenzo Librandi, Sep 30 2011


CROSSREFS

Cf. A168415, A104066.
Sequence in context: A267437 A267438 A102273 * A104066 A184394 A060160
Adjacent sequences: A195460 A195461 A195462 * A195464 A195465 A195466


KEYWORD

nonn,easy


AUTHOR

Brad Clardy, Sep 19 2011


STATUS

approved



