OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..11306
EXAMPLE
There are three repetitions of 5 because of the sets {{{{{}}}}}, {{{}, {{}}}}, and {{{{}}}, {}}.
MAPLE
b:= proc(n) a(n):= `if`(n<2, n, add(a(n-k)*add(b(d)*d*
(-1)^(k/d+1), d=numtheory[divisors](k)), k=1..n-1)/(n-1))
end:
T:= n-> n$b(n):
seq(T(n), n=1..10); # Alois P. Heinz, May 05 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Joshua Zucker, Nov 10 2011
EXTENSIONS
Second set in example corrected by Rick L. Shepherd, May 22 2013
STATUS
approved