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A045802
2-ish numbers (end in 03, 21, 29, 47).
1
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
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
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
More terms from Erich Friedman.
STATUS
approved