OFFSET
1,2
EXAMPLE
All solutions for n=3
.-1...-3...-4...-3...-1...-2...-2
.-1....2....3...-3....0....1...-2
..2....2....3....4....0....1....3
MATHEMATICA
AatE[n_, nminusfE_, E_] := AatE[n, nminusfE, E] = Module[{a, fEminus, fEplus, f0, resn}, If[E == 0, If[n == 0, 1, 0], a = 0; For[fEminus = 0, fEminus <= nminusfE, fEminus++, For[fEplus = 0, fEplus <= nminusfE - fEminus, fEplus++, f0 = nminusfE - fEminus - fEplus; resn = n - (2^E + 1)*fEminus + (2^E - 1)*fEplus; If[Abs[resn] <= (1 + 2^(E - 1))*f0, a = a + AatE[resn, f0, E - 1]]]]; a]];
a[n_] := a[n] = AatE[n, n, 2 n - 2];
Table[Print[n, " ", a[n]]; a[n], {n, 1, 30}] (* Jean-François Alcover, Sep 18 2024, after R. J. Mathar in A187988 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 18 2011
EXTENSIONS
a(10)-a(30) from Jean-François Alcover, Sep 18 2024
STATUS
approved