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A230950
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Boustrophedon transform of Thue-Morse sequence A010060.
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5
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0, 1, 3, 6, 15, 50, 186, 834, 4243, 24318, 154780, 1083952, 8280624, 68531308, 610796150, 5832677415, 59411150931, 642979374958, 7368000716808, 89121684577460, 1134732527849730, 15170256449030866, 212469074496520610, 3111026318662704255, 47532980801984327584
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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LINKS
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J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon transform, J. Combin. Theory, 17A 44-54 1996 (Abstract, pdf, ps).
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FORMULA
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MATHEMATICA
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T[n_, k_] := (n!/k!) SeriesCoefficient[(1 + Sin[x])/Cos[x], {x, 0, n - k}];
a[n_] := Sum[T[n, k] ThueMorse[k], {k, 0, n}];
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PROG
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(Haskell)
a230950 n = sum $ zipWith (*) (a109449_row n) $ map fromIntegral a010060_list
(Python)
from itertools import count, islice, accumulate
def A230950_gen(): # generator of terms
blist = tuple()
for i in count(0):
yield (blist := tuple(accumulate(reversed(blist), initial=i.bit_count()&1)))[-1]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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