A045809 9-ish numbers (end in 13, 37, 59, 91).

13, 37, 59, 91, 113, 137, 159, 191, 213, 237, 259, 291, 313, 337, 359, 391, 413, 437, 459, 491, 513, 537, 559, 591, 613, 637, 659, 691, 713, 737, 759, 791, 813, 837, 859, 891, 913, 937, 959, 991, 1013, 1037, 1059, 1091, 1113, 1137, 1159, 1191, 1213, 1237

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1).

Formula

G.f.: x*(13+24*x+22*x^2+32*x^3+9*x^4)/(1-x-x^4+x^5). - Colin Barker, Jan 23 2012

a(n) = (50*n+4*i^(n*(n-1))+3*(-1)^n-25)/2, where i=sqrt(-1). - Bruno Berselli, Feb 22 2012

Mathematica

CoefficientList[Series[(13 + 24*x + 22*x^2 + 32*x^3 + 9*x^4)/(1 - x - x^4 + x^5), {x, 0, 80}], x] (* Wesley Ivan Hurt, Jan 23 2017 *)
LinearRecurrence[{1, 0, 0, 1, -1}, {13, 37, 59, 91, 113}, 50] (* Harvey P. Dale, Feb 03 2024 *)

Prog

(Haskell)
import Data.List (findIndices)
a045809 n = a045809_list !! (n-1)
a045809_list = findIndices (`elem` [13, 37, 59, 91]) $ cycle [0..99]
-- Reinhard Zumkeller, Jan 23 2012

Crossrefs

Cf. A045800-A045808, A045572, A045797, A045798.

Sequence in context: A353198 A217734 A319969 * A238675 A140112 A089030

Adjacent sequences: A045806 A045807 A045808 * A045810 A045811 A045812

Keyword

nonn,base,easy

Author

J. H. Conway

Extensions

More terms from Erich Friedman.

Status

approved