A045802 2-ish numbers (end in 03, 21, 29, 47).

3, 21, 29, 47, 103, 121, 129, 147, 203, 221, 229, 247, 303, 321, 329, 347, 403, 421, 429, 447, 503, 521, 529, 547, 603, 621, 629, 647, 703, 721, 729, 747, 803, 821, 829, 847, 903, 921, 929, 947, 1003, 1021, 1029, 1047, 1103, 1121, 1129, 1147, 1203, 1221

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*(3+18*x+8*x^2+18*x^3+53*x^4)/(1-x-x^4+x^5). - Colin Barker, Jan 23 2012

a(n) = (50*n-24*i^(n*(n+1))-7*(-1)^n-75)/2, where i=sqrt(-1). - Bruno Berselli, Feb 23 2012

a(1)=3, a(2)=21, a(3)=29, a(4)=47, a(5)=103, a(n)=a(n-1)+a(n-4)-a(n-5) .[Harvey P. Dale, May 05 2012]

Mathematica

Join[{3}, Select[Range[10, 1300], MemberQ[{{0, 3}, {2, 1}, {2, 9}, {4, 7}}, Take[ IntegerDigits[#], -2]]&]] (* or *) LinearRecurrence[{1, 0, 0, 1, -1}, {3, 21, 29, 47, 103}, 50] (* Harvey P. Dale, May 05 2012 *)

Prog

(Haskell)
import Data.List (findIndices)
a045802 n = a045802_list !! (n-1)
a045802_list = findIndices (`elem` [3, 21, 29, 47]) $ cycle [0..99]
-- Reinhard Zumkeller, Jan 23 2012

Crossrefs

Cf. A045800-A045809, A045572, A045797, A045798.

Sequence in context: A091103 A363409 A292310 * A006133 A317860 A039766

Adjacent sequences: A045799 A045800 A045801 * A045803 A045804 A045805

Keyword

nonn,base,easy

Author

J. H. Conway.

Extensions

More terms from Erich Friedman.

Status

approved