|
|
A230958
|
|
Boustrophedon transform of Thue-Morse sequence A001285.
|
|
3
|
|
|
1, 3, 7, 15, 39, 127, 480, 2143, 10907, 62495, 397814, 2785861, 21282228, 176133285, 1569817724, 14990658724, 152693582275, 1652531857935, 18936620009722, 229053108410969, 2916394751599614, 38989325834726043, 546070266163669664, 7995699956778626764
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon transform, J. Combin. Theory Ser. A, 76(1) (1996), 44-54 (Abstract, pdf, ps).
|
|
FORMULA
|
|
|
MATHEMATICA
|
T[n_, k_] := (n!/k!) SeriesCoefficient[(1 + Sin[x])/Cos[x], {x, 0, n - k}];
tm[n_] := Mod[Sum[Mod[Binomial[n, k], 2], {k, 0, n}], 3];
|
|
PROG
|
(Haskell)
a230958 n = sum $ zipWith (*) (a109449_row n) $ map fromIntegral a001285_list
(Python)
from itertools import accumulate, count, islice
def A230958_gen(): # generator of terms
blist = tuple()
for i in count(0):
yield (blist := tuple(accumulate(reversed(blist), initial=2 if i.bit_count()&1 else 1)))[-1]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|