A045804 4-ish numbers (end in 09, 41, 63, 87).

9, 41, 63, 87, 109, 141, 163, 187, 209, 241, 263, 287, 309, 341, 363, 387, 409, 441, 463, 487, 509, 541, 563, 587, 609, 641, 663, 687, 709, 741, 763, 787, 809, 841, 863, 887, 909, 941, 963, 987, 1009, 1041, 1063, 1087, 1109, 1141, 1163, 1187, 1209, 1241

Offset: 1

Author

J. H. Conway

Keywords

• nonn
• base
• easy

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).

Crossrefs

Cf. A045800-A045809.

Cf. A045572, A045797, A045798.

Programs

Haskell

import Data.List (findIndices)
a045804 n = a045804_list !! (n-1)
a045804_list = findIndices (`elem` [9,41,63,87]) $ cycle [0..99]
-- Reinhard Zumkeller, Jan 23 2012

Mathematica

Select[Range[1250],MemberQ[{9,41,63,87},Mod[#,100]]&] (* Harvey P. Dale, Aug 01 2020 *)

Formula

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

Extensions

More terms from Erich Friedman.