OFFSET
0,2
COMMENTS
Boustrophedon transform of A001405.
MATHEMATICA
nmax = 24; CoefficientList[Series[(Sec[x] + Tan[x]) (BesselI[0, 2 x] + BesselI[1, 2 x]), {x, 0, nmax}], x] Range[0, nmax]!
t[n_, 0] := Binomial[n, Floor[n/2]]; t[n_, k_] := t[n, k] = t[n, k - 1] + t[n - 1, n - k]; a[n_] := t[n, n]; Array[a, 25, 0]
PROG
(Python)
from itertools import accumulate, count, islice
def A306799_gen(): # generator of terms
blist, a = tuple(), 1
for i in count(1):
yield (blist := tuple(accumulate(reversed(blist), initial=a)))[-1]
a = 2*a*i//(i+1) if i & 1 else 2*a
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 16 2019
STATUS
approved