A045800 0-ish numbers (end in 01, 07, 43, 49).

1, 7, 43, 49, 101, 107, 143, 149, 201, 207, 243, 249, 301, 307, 343, 349, 401, 407, 443, 449, 501, 507, 543, 549, 601, 607, 643, 649, 701, 707, 743, 749, 801, 807, 843, 849, 901, 907, 943, 949, 1001, 1007, 1043, 1049, 1101, 1107, 1143, 1149, 1201, 1207

Offset

1,2

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*(1+6*x+36*x^2+6*x^3+51*x^4)/(1-x-x^4+x^5). - Colin Barker, Jan 23 2012

a(n) = (50*n-8*i^(n*(n+1))-19*(-1)^n-75)/2, where i=sqrt(-1). - Bruno Berselli, Feb 22 2012

Mathematica

LinearRecurrence[{1, 0, 0, 1, -1}, {1, 7, 43, 49, 101}, 60] (* Harvey P. Dale, Jul 26 2015 *)

Prog

(Haskell)
import Data.List (findIndices)
a045800 n = a045800_list !! (n-1)
a045800_list = findIndices (`elem` [1, 7, 43, 49]) $ cycle [0..99]
-- Reinhard Zumkeller, Jan 23 2012

Crossrefs

Cf. A045801-A045809, A045572, A045797, A045798.

Sequence in context: A173828 A376506 A376541 * A159254 A062336 A085704

Adjacent sequences: A045797 A045798 A045799 * A045801 A045802 A045803

Keyword

nonn,base,easy

Author

J. H. Conway.

Extensions

More terms from Erich Friedman.

Status

approved