OFFSET
1,2
COMMENTS
Through the first 200 terms, the largest term has 6 digits with the exception of a(99) which has 134 digits. - Harvey P. Dale, Dec 24 2018
EXAMPLE
MATHEMATICA
rd[x_] :=FromDigits[Reverse[IntegerDigits[x]]] Table[GCD[rd[w! ], rd[(w+1)! ]], {w, 1, 100}]
GCD@@#&/@Partition[IntegerReverse[Range[100]!], 2, 1] (* Harvey P. Dale, Dec 24 2018 *)
PROG
(Python)
from math import factorial, gcd
def a(n):
f = factorial(n)
return gcd(int(str(f)[::-1]), int(str(f*(n+1))[::-1]))
print([a(n) for n in range(1, 64)]) # Michael S. Branicky, Dec 12 2021
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Jan 25 2005
STATUS
approved