OFFSET
1,2
COMMENTS
FORMULA
It appears that a(n)~4.1*n.
MATHEMATICA
a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/2), {x, 0, l}], x]]] != True, k++ ]; k]; Position[ Table[a[n], {n, 0, 300}], 1] // Flatten
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna and Robert G. Wilson v, Nov 08 2005
STATUS
approved