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G.f.: 1/(1-xy-2x^2/(1-x^2/(1-x^2/(1-x^2/(1-.... (continued fraction). [_- _Paul Barry_, Jan 28 2009]
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0, 1;
2, 0, 1;
0, 4, 0, 1;
6, 0, 6, 0, 1;
0, 16, 0, 8, 0, 1;
0, 0;
2, 0, 0;
0, 4, 0, 0;
0, 0, 6, 0, 0;
0, 0, 0, 8, 0, 0; (End)
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Row sums are A098615.
Binomial transform (product with C(n,k)) is A111960.
Diagonal sums are A026671 (with interpolated zeros).
Row sums are A098615. Binomial transform (product with C(n,k)) is A111960. Diagonal sums are A026671 (with interpolated zeros). Inverse is (1/sqrt(1+4x^2),x/sqrt(1+4x^2)), or (sqrt(-1))^(n-k)*T(n,k); . [corrected by Peter Bala, Aug 13 2021.]
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Riordan array (1/sqrt(1-4x^2), x/sqrt(1-4x^2)); Number number triangle T(n, k)=(1+(-1)^(n-k))*binomial((n-1)/2, (n-k)/2)*2^(n-k)/2.
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