A045806 6-ish numbers (end in 23, 27, 61, 89).
23, 27, 61, 89, 123, 127, 161, 189, 223, 227, 261, 289, 323, 327, 361, 389, 423, 427, 461, 489, 523, 527, 561, 589, 623, 627, 661, 689, 723, 727, 761, 789, 823, 827, 861, 889, 923, 927, 961, 989, 1023, 1027, 1061, 1089, 1123, 1127, 1161, 1189, 1223, 1227
Offset: 1
Links
- Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
Programs
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Haskell
import Data.List (findIndices) a045806 n = a045806_list !! (n-1) a045806_list = findIndices (`elem` [23,27,61,89]) $ cycle [0..99] -- Reinhard Zumkeller, Jan 23 2012
Formula
Empirical g.f.: x*(23+4*x+34*x^2+28*x^3+11*x^4)/(1-x-x^4+x^5). - Colin Barker, Jan 23 2012
Extensions
More terms from Erich Friedman