A323318 G.f. A(x) satisfies: 1 = Sum_{n>=0} ( (1+x)^n - 15*x*A(x) )^n * 7^n / 8^(n+1).

1, 119, 53473, 40508503, 41741036561, 53428266259151, 80958982980046129, 141048455946249441191, 277099512762218200167617, 605370915659340921493495687, 1455268739680049030318517763457, 3817384299846582450604884256739951, 10851817459553385455156107655677525601, 33237713019302068995081812342685224005719, 109138923772997447194531532072327732171764385

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

G.f. A(x) satisfies the following identities.

(1) 1 = Sum_{n>=0} ( (1+x)^n - 15*x*A(x) )^n * 7^n / 8^(n+1).

(2) 1 = Sum_{n>=0} (1+x)^(n^2) * 7^n / (8 + 105*x*A(x)*(1+x)^n)^(n+1).

Example

G.f.: A(x) = 1 + 119*x + 53473*x^2 + 40508503*x^3 + 41741036561*x^4 + 53428266259151*x^5 + 80958982980046129*x^6 + 141048455946249441191*x^7 + ...
such that
1 = 1/8 + ((1+x) - 15*x*A(x))*7/8^2 + ((1+x)^2 - 15*x*A(x))^2*7^2/8^3 + ((1+x)^3 - 15*x*A(x))^3*7^3/8^4 + ((1+x)^4 - 15*x*A(x))^4*7^4/8^5 + ...
Also,
1 = 1/(8 + 105*x*A(x)) + (1+x)*7/(8 + 105*x*A(x)*(1+x))^2 + (1+x)^4*7^2/(8 + 105*x*A(x)*(1+x)^2)^3 + (1+x)^9*7^3/(8 + 105*x*A(x)*(1+x)^3)^4 + ...

Prog

(PARI) \p120
{A=vector(1); A[1]=1; for(i=1, 20, A = concat(A, 0);
A[#A] = round( Vec( sum(n=0, 2000, ( (1+x +x*O(x^#A))^n - 15*x*Ser(A) )^n * 7^n/8^(n+1)*1.)/105 ) )[#A+1]); A}

Crossrefs

Cf. A301435, A303288, A323314, A323315, A323316, A323317, A323319, A323320, A323321.

Sequence in context: A184330 A210044 A020546 * A192726 A266032 A269123

Adjacent sequences: A323315 A323316 A323317 * A323319 A323320 A323321

Keyword

nonn

Author

Paul D. Hanna, Jan 10 2019

Status

approved