OFFSET
1,8
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..400
EXAMPLE
a(7) = 1: [2,5];
a(8) = 3: [2,2,2,2], [4,4], [2,6];
a(9) = 4: [2,2,2,3], [3,3,3], [4,5], [2,7];
a(10) = 5: [2,2,3,3], [2,2,2,4], [3,3,4], [4,6], [2,8];
a(11) = 7: [2,3,3,3], [2,2,3,4], [3,4,4], [2,2,2,5], [3,3,5], [4,7], [2,9].
MAPLE
b:= proc(n, j, t, s) option remember;
add (b(n-i, i, irem(t+1, s), s), i=j..iquo(n, 2))+
`if`(igcd(t, s)>1, 1, 0)
end:
a:= n-> add (b(n-i, i, 2, i), i=2..iquo(n, 2)):
seq (a(n), n=1..60);
MATHEMATICA
b[n_, j_, t_, s_] := b[n, j, t, s] = Sum[b[n-i, i, Mod[t+1, s], s], {i, j, Quotient[n, 2]}] + If[GCD[t, s]>1, 1, 0]; a[n_] := Sum [b[n-i, i, 2, i], {i, 2, Quotient[n, 2]}]; Table[a[n], {n, 1, 60}] (* Jean-François Alcover, Feb 15 2017, translated from Maple *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 25 2011
STATUS
approved