login
A330030
Least k such that Sum_{i=0..n} k^n / i! is a positive integer.
2
1, 1, 2, 3, 6, 30, 30, 42, 210, 42, 210, 2310, 2310, 30030, 30030, 30030, 30030, 39270, 510510, 1939938, 9699690, 9699690, 9699690, 17160990, 223092870, 903210, 223092870, 223092870, 223092870, 6469693230, 6469693230, 200560490130, 200560490130, 10555815270, 200560490130
OFFSET
0,3
COMMENTS
Least k > 0 such that k^n/A061355(n) is an integer.
LINKS
FORMULA
a(n) = A007947(A061355(n)).
EXAMPLE
For n = 7, the denominator of Sum_{i=0..7} 1/i! is 252 = 2^2*3^2*7, so a(7) = 2*3*7 = 42.
PROG
(PARI) a(n) = factorback(factorint(denominator(sum(i=2, n, 1/i!)))[, 1]);
CROSSREFS
KEYWORD
nonn
AUTHOR
Jinyuan Wang, Mar 07 2020
STATUS
approved