A045805 5-ish numbers (end in 51, 57, 93, 99).

51, 57, 93, 99, 151, 157, 193, 199, 251, 257, 293, 299, 351, 357, 393, 399, 451, 457, 493, 499, 551, 557, 593, 599, 651, 657, 693, 699, 751, 757, 793, 799, 851, 857, 893, 899, 951, 957, 993, 999, 1051, 1057, 1093, 1099, 1151, 1157, 1193, 1199, 1251, 1257

Offset: 1

Author

J. H. Conway

Keywords

• nonn
• base
• easy

Links

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

Crossrefs

Cf. A045800-A045809.

Cf. A045572, A045797, A045798.

Programs

Haskell

import Data.List (findIndices)
a045805 n = a045805_list !! (n-1)
a045805_list = findIndices (`elem` [51,57,93,99]) $ cycle [0..99]
-- Reinhard Zumkeller, Jan 23 2012

Mathematica

Select[Range[50,1500],MemberQ[{51,57,93,99},Mod[#,100]]&] (* Harvey P. Dale, Nov 14 2022 *)

Formula

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

Extensions

More terms from Erich Friedman