OFFSET
1,1
COMMENTS
EXAMPLE
a(2)=3 because there are 3 numbers whose sum of factorials of the digits equals 2: 2, 10, 11.
MATHEMATICA
permC[w_] := Length[w]!/Times @@ ((Last /@ Tally[w])!); a[1]=2; a[n_] := Block[{s = 0, w, f = {1}}, While[Last[f] < n, AppendTo[f, Last[f] (Length[f] + 1)]]; Do[ p = IntegerPartitions[k, {1, k}, f]; Do[ If[k == n, s += permC[q], w = Join[q, 0 Range[n - k]]; s += permC[w] - permC[Most[w]]], {q, p}], {k, n}]; s]; Array[a, 32] (* Giovanni Resta, Mar 24 2020 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Mateusz Winiarski, Mar 24 2020
EXTENSIONS
More terms from Giovanni Resta, Mar 24 2020
STATUS
approved