OFFSET
1,2
COMMENTS
The greatest common divisor condition was suggested by A061446.
LINKS
PROG
(Haskell)
a126025 n = h n1s 0 where
h us c = if us == nns then c + 1 else h (succ us) (c + g) where
g = if and [f x `gcd` f y == f (x `gcd` y) |
x <- [1 .. n - 1], y <- [x + 1 .. n]] then 1 else 0
f = (us !!) . subtract 1
succ (z:zs) = if z < n then (z + 1) : zs else 1 : succ zs
n1s = take n [1, 1 ..]; nns = take n [n, n ..]
-- Reinhard Zumkeller, May 04 2014
CROSSREFS
KEYWORD
nonn,more,nice
AUTHOR
John W. Layman, Feb 27 2007
EXTENSIONS
a(10)-a(22) from Manfred Scheucher, Jun 06 2015
a(23) from Manfred Scheucher, Aug 13 2015
STATUS
approved