OFFSET
0,2
FORMULA
a(n) = 2^n*Sum_{k=0..n} A172094(n,k) / 2^k.
a(n) = [x^n] (1 + 6*x - 3*(4*x^2 - 12*x + 1)^(1/2))/(30*x - 2).
a(n) = (60*(n - 3)*a(n-3) + (282 - 184*n)*a(n-2) + (27*n - 18)*a(n-1)) / n.
MAPLE
gf := (1+6*x-3*(4*x^2-12*x+1)^(1/2))/(30*x-2): ser := series(gf, x, 32):
seq(coeff(ser, x, n), n=0..20);
MATHEMATICA
RecurrenceTable[{a[n] == (60 a[n - 3] (n - 3) + (-184 n + 282) a[n - 2] + (27*n - 18) a[n - 1])/n, a[0] == 1, a[1] == 3, a[2] == 21}, a, {n, 20}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Feb 02 2020
STATUS
approved