OFFSET
1,3
COMMENTS
Indices of positive terms in Stirling's asymptotic expansion of the Gamma-function.
If the conjecture is true, this entry will be removed as a duplicate of A042963. - R. J. Mathar, Nov 06 2015
FORMULA
a(1) = 0.
Conjecture: for n > 1, a(n) = ((-1)^n + 4*n - 7)/2.
MATHEMATICA
Module[{a}, a[0] = 1; a[n_] := a[n] = (a[n-1]/n - Sum[a[k] a[n-k]/(k+1), {k, 1, n-1}])/(1+1/(n+1)); Select[Range[0, 200], a[2#]>0&]]
PROG
(PARI) a(k) = local(A, m); if(k<1, k==0, A=vector(m=2*k+1, t, 1); for(t=2, m, A[t]=(A[t-1]-sum(i=2, t-1, i*A[i]*A[t+1-i]))/(t+1)); numerator(A[m]*m!/2^k/k!))
for(k=0, 100, if(a(k) > 0, print1(k", "))) \\ Altug Alkan, Nov 04 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Reshetnikov, Nov 03 2015
STATUS
approved