OFFSET
1,2
COMMENTS
Similar to A270875 but also counts singletons, the trivial solutions.
LINKS
Hiroaki Yamanouchi, Table of n, a(n) for n = 1..200
FORMULA
a(n) = A270875(n) + n.
MATHEMATICA
Table[Length@ Select[Rest@ Subsets@ Range@ n, Total@ # == LCM @@ # &], {n, 22}] (* Michael De Vlieger, Mar 27 2016 *)
PROG
(PARI) a(n) = {nb = 0; S = vector(n, k, k); for (i = 0, 2^n - 1, ss = vecextract(S, i); if (sum(k=1, #ss, ss[k]) == lcm(ss), nb++); ); nb; }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Mar 27 2016
EXTENSIONS
a(31)-a(58) from Hiroaki Yamanouchi, Mar 30 2016
STATUS
approved