OFFSET
1,2
COMMENTS
LINKS
Alois P. Heinz and Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 2000 terms from Alois P. Heinz)
MAPLE
with(combinat): with(numtheory):
b:= proc(n) option remember;
`if`(n=1, {}, b(n-1) union factorset(numbpart(n)))
end:
a:= n-> `if`(n=1, 1, max(1, (b(n) minus b(n-1))[])):
seq(a(n), n=1..120); # Alois P. Heinz, Aug 21 2011
MATHEMATICA
a[n_] := Complement[FactorInteger[PartitionsP[n]][[All, 1]], FactorInteger[Product[PartitionsP[k], {k, 1, n-1}]][[All, 1]]] /. {} -> {1} // Last; Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Jan 28 2014 *)
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Jonathan Sondow, Aug 21 2011
STATUS
approved