A227289 Smallest m such that gcd(A227113(m+1), A227113(m)) = n.

1, 2, 4, 10, 6, 177, 8, 514, 500, 349, 14, 4791, 16, 5949, 1623, 863, 20, 2629, 22, 5113, 2043, 3211, 28, 7347, 4593, 11911, 1647, 12819, 34, 27325, 36, 15755, 34527, 29319, 5459, 2797, 42, 24535, 20145, 15511, 46, 26523, 48, 64895, 13335, 40769, 54, 43835, 184041

Offset: 1

Author

Reinhard Zumkeller, Jul 05 2013

Keywords

• nonn

Comments

A227288(a(n)) = n and A227288(m) <> n for m < a(n).

Examples

			.   n |   a(n) | A227288(a(n)) = gcd(A227113(a(n)),A227113(a(n)+1))
.  ---+--------+--------------- -----------------------------------
.   1 |     1  |            1  =  gcd(1,2)
.   2 |     2  |            2  =  gcd(2,4)
.   3 |     4  |            3  =  gcd(3,6)
.   4 |    10  |            4  =  gcd(8,12)
.   5 |     6  |            5  =  gcd(5,10)
.   6 |   177  |            6  =  gcd(168,162)
.   7 |     8  |            7  =  gcd(7,14)
.   8 |   514  |            8  =  gcd(472,480)
.   9 |   500  |            9  =  gcd(459,468)
.  10 |   349  |           10  =  gcd(330,320)
.  11 |    14  |           11  =  gcd(11,22)
.  12 |  4791  |           12  =  gcd(4524,4512)
		

Programs

Haskell

import Data.List (elemIndex); import Data.Maybe (fromJust)
a227289 = (+ 1) . fromJust . (`elemIndex` a227288_list)