A185635 Fixed points of A075075.

1, 2, 8, 36, 39, 49, 370, 626, 632, 1030, 13155, 32317, 61358, 86704, 2535431, 13360009

Offset: 1

Author

Reinhard Zumkeller, Dec 19 2012

Keywords

• nonn
• more

Comments

A075075(a(n)) = A160516(a(n)) = a(n);

A075075(a(n)-1) * A075075(a(n)+1) mod a(n) = 0.

Programs

Haskell

a185635 n = a185635_list !! (n-1)
a185635_list = filter (> 0) $
   zipWith (\x y -> if x == y then y else 0) [1..] a075075_list
-- Reinhard Zumkeller, Dec 19 2012

Python

from math import gcd
A185635_list, l1, l2, m, b = [1, 2], 2, 1, 2, {1, 2}
for n in range(3, 10**4):
    i = m
    while True:
        if not i in b:
            if n == i:
                A185635_list.append(i)
            l1, l2, m = i, l1, i//gcd(l1, i)
            b.add(i)
            break
        i += m # Chai Wah Wu, Dec 09 2014

Extensions

a(15) from Chai Wah Wu, Dec 10 2014

a(16) from Chai Wah Wu, Sep 22 2019