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A122448 A lower diagonal of pendular trinomial triangle A122445. 7
1, 1, 3, 10, 36, 135, 525, 2094, 8524, 35266, 147862, 626884, 2682940, 11575707, 50295809, 219879814, 966487380, 4268781902, 18936044682, 84326759820, 376853237480, 1689551241606, 7597003401186, 34251504489484 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

G.f.: A(x) = B(x)/(1+x - x*B(x) ) where B(x) is the g.f. of A122446.

FORMULA

G.f. satisfies: A(x) = 1 + x*(1-2*x-2*x^2)*A(x) + x^2*(4+3*x)*A(x)^2. G.f.: A(x) = 2/(1-x+2*x^2+2*x^3 + (1+x)*sqrt(1-4*x-4*x^2+4*x^4)).

PROG

(PARI) {a(n)=polcoeff(2/(1-x+2*x^2+2*x^3+(1+x)*sqrt(1-4*x-4*x^2+4*x^4+x*O(x^n))), n)}

CROSSREFS

Cf. A122445, A122446, A122447, A122449, A122450, A122451, A122452.

Sequence in context: A126188 A081909 A126189 * A007582 A026854 A136576

Adjacent sequences:  A122445 A122446 A122447 * A122449 A122450 A122451

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Sep 07 2006

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Last modified February 16 17:11 EST 2012. Contains 205938 sequences.