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 1-4 of 4 results.

A377664 a(n) = Sum_{j=0..n} binomial(n, j)*Euler(j, 0)*(2*n)^j. Main diagonal of A377666.

Original entry on oeis.org

1, 0, -3, 46, 497, -47524, -737891, 218380506, 4534099905, -3027853088648, -79034002960099, 99913537539058310, 3145444161956190577, -6725392006687056786732, -248035037340684934103427, 829076907459643714597871026, 35061737998144136797680434945, -172868475620109085260017037166096
Offset: 0

Views

Author

Peter Luschny, Nov 14 2024

Keywords

Crossrefs

Cf. A377666.

Programs

  • Maple
    a := n -> local j; add(binomial(n, j)*euler(j, 0)*(2*n)^j, j = 0..n):
    seq(a(n), n = 0..16);
  • Mathematica
    a[0] := 1; a[n_] := Sum[Binomial[n, j] EulerE[j, 0] (2n)^j, {j, 0, n}];
    Table[a[n], {n, 0, 16}]
  • Python
    from math import comb
    from sympy import euler
    def A377664(n): return sum(comb(n,j)*euler(j,0)*(n<<1)**j for j in range(n+1)) # Chai Wah Wu, Nov 14 2024

A377665 a(n) = Sum_{j=0..n} binomial(n, j) * Euler(j, 0) * 10^j. Row 5 of A377666.

Original entry on oeis.org

1, -4, -9, 236, 981, -47524, -295029, 20208716, 167213961, -14741279044, -152462570049, 16429489441196, 203906790454941, -25968596099278564, -376012858170009069, 55254540434093713676, 914353480122881739921, -152277985980992039230084, -2834887281233334168196089
Offset: 0

Views

Author

Peter Luschny, Nov 13 2024

Keywords

Crossrefs

Cf. A377666.

Programs

  • Maple
    a := n -> local j; add(binomial(n, j)*euler(j, 0)*10^j, j = 0..n):
    # Alternative:
    a := n -> add(10^j*(1-2^j)*bernoulli(j)*binomial(n+1, j), j = 0..n+1) / (5*(n+1)):
    seq(a(n), n = 0..18);
  • Mathematica
    a[n_] := 5^n (4^(n+1) HurwitzZeta[-n, 1/(20)] - 2^(n + 1) HurwitzZeta[-n, 1/(10)]);
    Table[Round[N[a[n], 64]], {n, 0, 18}]
  • SageMath
    from mpmath import *
    mp.dps = 32; mp.pretty = True
    def a(n): return int(imag(2*I*(1+sum(binomial(n, j)*polylog(-j, I)*5^j for j in range(n+1)))))
    print([a(n) for n in range(19)])

Formula

a(n) = 2^(n + 1) * 5^n * (2^(n + 1) * HurwitzZeta(-n, 1/20) - HurwitzZeta(-n, 1/10)).
a(n) = Im(p(n)) where p(n) = 2*i*(1 + Sum_{j=0..n} binomial(n, j)*polylog(-j, i)*5^j).
a(n) = (1/(5*(n+1))) * Sum_{j=0..n+1} Bernoulli(j, 0) * binomial(n+1, j) * (10^j - 20^j).

A378066 Array read by ascending antidiagonals: A(n, k) = (-2*n)^k * Euler(k, (n - 1)/(2*n)) for n >= 1 and A(0, k) = 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, -3, -2, 1, 1, 1, -8, -11, 0, 1, 1, 1, -15, -26, 57, 16, 1, 1, 1, -24, -47, 352, 361, 0, 1, 1, 1, -35, -74, 1185, 1936, -2763, -272, 1, 1, 1, -48, -107, 2976, 6241, -38528, -24611, 0, 1
Offset: 0

Views

Author

Peter Luschny, Nov 15 2024

Keywords

Comments

This is the counterpart of A377666, where A(1, n) are the secant numbers A122045(n). Here A(1, n) are the tangent numbers A155585(n).

Examples

			Array starts:
  [0]  1, 1,   1,    1,     1,     1,        1, ...  A000012
  [1]  1, 1,   0,   -2,     0,    16,        0, ...  A155585
  [2]  1, 1,  -3,  -11,    57,   361,    -2763, ...  A188458
  [3]  1, 1,  -8,  -26,   352,  1936,   -38528, ...  A000810
  [4]  1, 1, -15,  -47,  1185,  6241,  -230895, ...  A000813
  [5]  1, 1, -24,  -74,  2976, 15376,  -906624, ...  A378065
  [6]  1, 1, -35, -107,  6265, 32041, -2749355, ...
  [7]  1, 1, -48, -146, 11712, 59536, -6997248, ...
		

Crossrefs

Columns: A005563 (k=2), A080663 (k=3), A378064 (k=4).
Cf. A378063 (main diagonal), A377666 (secant), A081658 (column generating polynomials).

Programs

  • Maple
    A := (n, k) -> ifelse(n = 0, 1, (-2*n)^k * euler(k, (n - 1) / (2*n))):
    for n from 0 to 7 do seq(A(n, k), k = 0..9) od; # row by row
    # Alternative:
    A := proc(n, k) local j; add(binomial(k, j)*euler(j, 1/2)*(-2*n)^j, j = 0..k) end: seq(seq(A(n - k, k), k = 0..n), n = 0..10);
    # Using generating functions:
    egf := n -> exp(x)/cosh(n*x): ser := n -> series(egf(n), x, 14):
    row := n -> local k; seq(k!*coeff(ser(n), x, k), k = 0..7):
    seq(lprint(row(n)), n = 0..7);

Formula

A(n, k) = k! * [x^k] exp(x)/cosh(n*x).
A(n, k) = Sum_{j = 0..k} binomial(k, j) * Euler(j, 1/2) *(-2*n)^j.

A377663 a(n) = 2*n^3 - 3*n + 1.

Original entry on oeis.org

1, 0, 11, 46, 117, 236, 415, 666, 1001, 1432, 1971, 2630, 3421, 4356, 5447, 6706, 8145, 9776, 11611, 13662, 15941, 18460, 21231, 24266, 27577, 31176, 35075, 39286, 43821, 48692, 53911, 59490, 65441, 71776, 78507, 85646, 93205, 101196, 109631, 118522, 127881, 137720
Offset: 0

Views

Author

Peter Luschny, Nov 14 2024

Keywords

Crossrefs

Column 3 of A377666.

Programs

  • Magma
    [2*n^3 - 3*n + 1 : n in [0..60]]; // Wesley Ivan Hurt, Aug 05 2025
  • Maple
    a := n -> 2*n^3 - 3*n + 1: seq(a(n), n = 0..41);
  • Mathematica
    LinearRecurrence[{4,-6,4,-1},{1, 0, 11, 46},42] (* James C. McMahon, Nov 14 2024 *)

Formula

a(n) = [x^n] (-2*x^3 + 17*x^2 - 4*x + 1)/(x - 1)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 3. - Chai Wah Wu, Nov 14 2024
Showing 1-4 of 4 results.