A256751 Index of A166133(n) in the list of divisors of A166133(n-1)^2 - 1.

2, 4, 3, 5, 2, 7, 2, 8, 3, 7, 4, 6, 4, 10, 8, 4, 12, 2, 11, 3, 10, 6, 11, 4, 8, 6, 12, 10, 4, 12, 4, 12, 8, 7, 4, 14, 2, 19, 5, 21, 3, 17, 7, 9, 7, 13, 4, 19, 7, 13, 5, 17, 5, 21, 9, 11, 5, 17, 3, 17, 7, 9, 13, 17, 5, 17, 6, 12, 5, 24, 4, 16, 12, 8, 6, 15, 2

Offset: 4

Author

Reinhard Zumkeller, Apr 09 2015

Keywords

• nonn

Comments

A166133(n) = A027750(A166133(n-1)^2-1,a(n)).

Examples

			n = 12: A166133(12) = 9, A166133(12-1) = 10, 10^2 - 1 = 99,
9 is the third term of divisors(99) = [1,3,9,11,33,99],
therefore a(12) = 3;
n = 13: A166133(13) = 16, A166133(13-1) = 9, 9^2 - 1 = 80,
16 is the seventh term of divisors(80) = [1,2,4,5,8,10,16,20,40,80],
therefore a(13) = 7.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 4..10000

Crossrefs

Cf. A166133, A027750.

Programs

Haskell

import Data.List (elemIndex); import Data.Maybe (fromJust)
a256751 n = (+ 1) $ fromJust $
            a166133 n `elemIndex` a027750_row' (a166133 (n - 1) ^ 2 - 1)