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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

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OFFSET

1,1

LINKS

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

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

PROG

(Haskell)

import Data.List (findIndices)

a045806 n = a045806_list !! (n-1)

a045806_list = findIndices (`elem` [23, 27, 61, 89]) $ cycle [0..99]