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A112971 Row sums of the matrix ((1,xc(x))^2 mod 2), where c(x) is the g.f. of A000108. 1
1, 1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 4, 2, 2, 1, 6, 3, 4, 2, 4, 2, 2, 1, 8, 4, 4, 2, 4, 2, 2, 1, 11, 6, 6, 3, 8, 4, 4, 2, 8, 4, 4, 2, 4, 2, 2, 1, 16, 8, 8, 4, 8, 4, 4, 2, 8, 4, 4, 2, 4, 2, 2, 1, 22, 11, 12, 6, 12, 6, 6, 3, 16, 8, 8, 4, 8, 4, 4, 2, 16, 8, 8, 4, 8, 4, 4, 2, 8, 4, 4, 2, 4, 2, 2, 1, 32, 16, 16, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

(1,xc(x)) is the Riordan array T(n,k)=[x^n](xc(x))^k. Conjectures: a(2^n)=a(2^(n+1)+1)=A005578(n);a(2^n-1)=a(3*2^n-1)=1.

LINKS

Table of n, a(n) for n=0..99.

FORMULA

a(n)=sum{k=0..n, mod(sum{i=0..n, sum{j=0..n, ((2j+1)/(n+j+1))(-1)^(j-i)C(2n, n+j)C(j, i)}* sum{l=0..i, ((2l+1)/(i+l+1))(-1)^(l-k)C(2i, i+l)C(l, k)}}, 2)}

CROSSREFS

Cf. A112970.

Sequence in context: A277692 A129138 A112970 * A299201 A050379 A153024

Adjacent sequences:  A112968 A112969 A112970 * A112972 A112973 A112974

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Oct 07 2005

STATUS

approved

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Last modified February 20 14:03 EST 2020. Contains 332078 sequences. (Running on oeis4.)