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A101691
A modular binomial sum sequence.
1
1, 1, 2, 1, 3, 1, 2, 2, 5, 1, 2, 2, 4, 2, 4, 4, 9, 1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 17, 1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 33, 1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8
OFFSET
0,3
COMMENTS
a(2^n)=A094373(n). a(2^n-1)=1,1,1,2,4,8,16,...
LINKS
FORMULA
a(n)=sum{k=0..n, mod(binomial(2n-2, k), 2)}
MATHEMATICA
Table[Sum[Mod[Binomial[2n-2, k], 2], {k, 0, n}], {n, 0, 100}] (* Harvey P. Dale, Oct 20 2011 *)
CROSSREFS
Cf. A048896.
Sequence in context: A037269 A124579 A035306 * A349445 A205379 A238881
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Dec 11 2004
STATUS
approved