cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A183066 G.f.: A(x) = (1 + 21*x + 3*x^2 - x^3)/(1-x)^5.

Original entry on oeis.org

1, 26, 123, 364, 845, 1686, 3031, 5048, 7929, 11890, 17171, 24036, 32773, 43694, 57135, 73456, 93041, 116298, 143659, 175580, 212541, 255046, 303623, 358824, 421225, 491426, 570051, 657748, 755189, 863070, 982111, 1113056, 1256673, 1413754, 1585115, 1771596
Offset: 0

Views

Author

Paul D. Hanna, Dec 22 2010

Keywords

Crossrefs

Programs

  • PARI
    {a(n)=polcoeff((1+21*x+3*x^2-x^3)/(1-x+x*O(x^n))^5,n)}

Formula

a(n) = A183065(n+1,1).

A183068 Central terms of triangle A183065.

Original entry on oeis.org

1, 26, 3246, 606500, 137915470, 35218238076, 9702014515116, 2818627826459016, 851612982884556750, 265166341958122567820, 84556145346599067308596, 27489903606068331188121816, 9081510922185418532993154796
Offset: 0

Views

Author

Paul D. Hanna, Dec 22 2010

Keywords

Crossrefs

Programs

  • Maple
    seq(simplify(binomial(2*n, n)*hypergeom([-n, -n, n+1, n+1/2], [1, 1, 1], 4)), n = 0..20);
  • PARI
    {a(n)=polcoeff(polcoeff(sum(m=0,2*n,(4*m)!/m!^4*x^(2*m)*y^m/(1-x-x*y+x*O(x^(2*n)))^(4*m+1)),2*n,x),n,y)}

Formula

a(n) = A183065(2*n,n).
a(n) = [x^(2*n)*y^n] Sum_{m >= 0} (4*m)!/m!^4 * x^(2*m)*y^m/(1-x-x*y)^(4*m+1).
From Peter Bala, Jul 15 2024: (Start)
a(n) = binomial(2*n, n)*Sum_{k = 0..n} binomial(n, k)^2*binomial(2*n+2*k, 2*k)* binomial(2*k, k) = Sum_{k = 0..n} (2*n+2*k)!/(k!^4*(n-k)!^2). Cf. A002897(n) = Sum_{k = 0..n} (2*n+k)!/(k!^3*(n-k)!^2) and A005258(n) = n!*Sum_{k = 0..n} (n+k)!/(k!^3*(n-k)!^2).
a(n) = binomial(2*n, n)*hypergeom([-n, -n, n+1, n+1/2], [1, 1, 1], 4).
Conjecture: the supercongruence a(n*p^r) == a(n*p^(r-1)) (mod p^(2*r)) holds for all primes p and positive integers n and r (End)
a(n) ~ sqrt(3) * (2 + sqrt(6))^(4*n + 3/2) / (16*Pi^2*n^2). - Vaclav Kotesovec, Jul 16 2024

A183065 Triangle defined by g.f.: Sum_{n>=0} (4*n)!/n!^4 * x^(2*n)*y^n/(1-x-x*y)^(4*n+1), read by rows.

Original entry on oeis.org

1, 1, 1, 1, 26, 1, 1, 123, 123, 1, 1, 364, 3246, 364, 1, 1, 845, 25210, 25210, 845, 1, 1, 1686, 120135, 606500, 120135, 1686, 1, 1, 3031, 430941, 6082475, 6082475, 430941, 3031, 1, 1, 5048, 1277668, 38698856, 137915470, 38698856, 1277668, 5048, 1, 1, 7929
Offset: 0

Views

Author

Paul D. Hanna, Dec 22 2010

Keywords

Comments

Compare the g.f. of this triangle with the g.f.s of triangles:
* A008459: Sum_{n>=0} (2n)!/n!^2 * x^(2n)*y^n/(1-x-xy)^(2n+1),
* A181543: Sum_{n>=0} (3n)!/n!^3 * x^(2n)*y^n/(1-x-xy)^(3n+1),
which have terms A008459(n,k) = C(n,k)^2 and A181543(n,k) = C(n,k)^3.

Examples

			G.f.: A(x,y) = 1/(1-x-xy) + 4!*x^2*y/(1-x-xy)^5 + (8!/2!^4)*x^4*y^2/(1-x-xy)^9 + (12!/3!^4)*x^6*y^3/(1-x-xy)^13 +...
Triangle begins:
1;
1, 1;
1, 26, 1;
1, 123, 123, 1;
1, 364, 3246, 364, 1;
1, 845, 25210, 25210, 845, 1;
1, 1686, 120135, 606500, 120135, 1686, 1;
1, 3031, 430941, 6082475, 6082475, 430941, 3031, 1;
1, 5048, 1277668, 38698856, 137915470, 38698856, 1277668, 5048, 1; ...
		

Crossrefs

Cf. A183066 (column 1), A183067 (row sums), A183068 (central terms).

Programs

  • PARI
    {T(n,k)=polcoeff(polcoeff(sum(m=0,n,(4*m)!/m!^4*x^(2*m)*y^m/(1-x-x*y+x*O(x^n))^(4*m+1)),n,x),k,y)}
Showing 1-3 of 3 results.