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.

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A363000 a(n) = numerator(R(n, n, 1)), where R are the rational polynomials R(n, k, x) = Sum_{u=0..k} ( Sum_{j=0..u} x^j * binomial(u, j) * (j + 1)^n ) / (u + 1).

Original entry on oeis.org

1, 5, 19, 188, 1249, 125744, 283517, 303923456, 138604561, 599865008128, 118159023973, 7078040993755136, 155792758736921, 146303841678548271104, 294014633772018349, 64670474732430319157248, 752324747622089633569, 3224753626003393505960919040, 2507759850059601711479669
Offset: 0

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Author

Peter Luschny, May 12 2023

Keywords

Comments

R(n, n, 0) are the (0-based) harmonic numbers, R(n, n, -1) are the Bernoulli numbers, and R(n, n, 1) is this sequence in its rational form.

Examples

			a(n) are the numerators of the terms on the main diagonal of the triangle:
[0] 1;
[1] 1,  5/2;
[2] 1,  7/2,  19/2;
[3] 1, 11/2, 121/6,  188/3;
[4] 1, 19/2,  95/2,  369/2,   1249/2;
[5] 1, 35/2, 721/6, 1748/3, 35164/15, 125744/15;
[6] 1, 67/2, 639/2, 3877/2,  18533/2,   76317/2, 283517/2;
		

Crossrefs

Cf. A363001 (denominators), A362999 (odd-indexed denominators), A362998.

Programs

  • Maple
    # For better context we put A362998, A362999, A363000, and A363001 together here.
    R := (n, k, x) -> add(add(x^j*binomial(u, j)*(j+1)^n, j=0..u)/(u + 1), u=0..k):
    ### x = 1 -> this sequence
     for n from 0 to 7 do [n], seq(R(n, k, 1), k = 0..n) od;
     seq(R(n, n, 1), n = 0..9);
     A363000 := n -> numer(R(n, n, 1)): seq(A363000(n), n = 0..10);
     A363001 := n -> denom(R(n, n, 1)): seq(A363001(n), n = 0..20);
     A362999 := n -> denom(R(2*n+1, 2*n+1, 1)): seq(A362999(n), n = 0..11);
     A362998 := n -> add(R(2*n, k, 1), k = 0..2*n): seq(A362998(n), n = 0..9);
    ### x = -1 -> Bernoulli(n, 1)
    # for n from 0 to 9 do [n], seq(R(n, k,-1), k = 0..n) od;
    # seq(R(n, n, -1), n = 0..12); seq(bernoulli(n, 1), n = 0..12);
    ### x = 0 -> Harmonic numbers
    # for n from 0 to 9 do [n], seq(R(n, k, 0), k = 0..n) od;
    # seq(R(n, n, 0), n = 0..9); seq(harmonic(n+1), n = 0..9);

Formula

Sum_{k=0..n} R(n, k, 0) = Sum_{j=0..n} (n-j+1)/(j+1) = (n+2)*Harmonic(n+1)-n-1.
Sum_{k=0..n} R(n, k,-1) = (n + 2 - 0^n) * Bernoulli(n, 1).
Sum_{k=0..2*n} R(2*n, k, 1) = A362998(n).
2*R(n, 1, 1) = A062709(n).

A363001 a(n) = denominator(R(n, n, 1)) where R(n, k, x) = Sum_{u=0..k} ( Sum_{j=0..u} x^j * binomial(u, j) * (j + 1)^n ) / (u + 1).

Original entry on oeis.org

1, 2, 2, 3, 2, 15, 2, 105, 2, 315, 2, 3465, 2, 45045, 2, 9009, 2, 153153, 2, 14549535, 2, 14549535, 2, 19684665, 2, 1673196525, 2, 5019589575, 2, 145568097675, 2, 4512611027925, 2, 4512611027925, 2, 4512611027925, 2, 166966608033225, 2, 316824683175, 2, 6845630929362225
Offset: 0

Views

Author

Peter Luschny, May 12 2023

Keywords

Comments

See A363000 for a discussion of the polynomials.

Crossrefs

Cf. A363000 (numerators), A362999 (odd-indexed denominators).

Programs

  • Maple
    # See A363000 for a program.
Showing 1-2 of 2 results.