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A047550 Numbers that are congruent to {5, 7} mod 8. 6
5, 7, 13, 15, 21, 23, 29, 31, 37, 39, 45, 47, 53, 55, 61, 63, 69, 71, 77, 79, 85, 87, 93, 95, 101, 103, 109, 111, 117, 119, 125, 127, 133, 135, 141, 143, 149, 151, 157, 159, 165, 167, 173, 175, 181, 183, 189, 191, 197, 199, 205, 207, 213, 215, 221, 223, 229, 231, 237, 239, 245, 247, 253, 255, 261 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

FORMULA

a(n) = 8*n-a(n-1)-4 (with a(1)=5). - Vincenzo Librandi, Aug 06 2010

a(n) = 4*n-(-1)^n. - Rolf Pleisch, Nov 02 2010

a(1)=5, a(2)=7, a(3)=13; for n>3, a(n) = a(n-1)+a(n-2)-a(n-3). - Harvey P. Dale, Jun 04 2012

G.f.: x*(5+2*x+x^2) / ((1-x)^2*(1+x)). - Colin Barker, Aug 26 2016

MAPLE

A047550:=n->4*n-(-1)^n; seq(A047550(n), n=1..100); # Wesley Ivan Hurt, Mar 31 2014

MATHEMATICA

With[{r8=8*Range[0, 40]}, Sort[Join[r8+5, r8+7]]] (* or *) LinearRecurrence[ {1, 1, -1}, {5, 7, 13}, 80] (* Harvey P. Dale, Jun 04 2012 *)

Table[4 n - (-1)^n, {n, 100}] (* Wesley Ivan Hurt, Mar 31 2014 *)

PROG

(PARI) Vec(x*(5+2*x+x^2)/((1-x)^2*(1+x)) + O(x^100)) \\ Colin Barker, Aug 26 2016

CROSSREFS

Sequence in context: A055052 A314314 A314315 * A179194 A314316 A314317

Adjacent sequences:  A047547 A047548 A047549 * A047551 A047552 A047553

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Vincenzo Librandi, Aug 06 2010

STATUS

approved

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Last modified May 24 18:34 EDT 2019. Contains 323534 sequences. (Running on oeis4.)