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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A258997 A(n,k) = pi-based antiderivative of n^k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 4, 2, 0, 0, 0, 12, 12, 4, 0, 0, 0, 32, 54, 32, 3, 0, 0, 0, 80, 216, 192, 30, 7, 0, 0, 0, 192, 810, 1024, 225, 84, 4, 0, 0, 0, 448, 2916, 5120, 1500, 756, 56, 12, 0, 0, 0, 1024, 10206, 24576, 9375, 6048, 588, 192, 12, 0
Offset: 0

Views

Author

Alois P. Heinz, Jun 27 2015

Keywords

Examples

			Square array A(n,k) begins:
  0, 0,  0,   0,    0,     0,      0,       0, ...
  0, 0,  0,   0,    0,     0,      0,       0, ...
  0, 1,  4,  12,   32,    80,    192,     448, ...
  0, 2, 12,  54,  216,   810,   2916,   10206, ...
  0, 4, 32, 192, 1024,  5120,  24576,  114688, ...
  0, 3, 30, 225, 1500,  9375,  56250,  328125, ...
  0, 7, 84, 756, 6048, 45360, 326592, 2286144, ...
  0, 4, 56, 588, 5488, 48020, 403368, 3294172, ...
		

Crossrefs

Rows n=0+1,2,3,4,8 give: A000004, A001787, A212697, A018215, A230539.
Columns k=0,1 give: A000004, A258851.
Main diagonal gives A258846.
Cf. A000720.

Programs

  • Maple
    with(numtheory):
    d:= n-> n*add(i[2]*pi(i[1])/i[1], i=ifactors(n)[2]):
    A:= (n, k)-> `if`(k=0, 0, k*n^(k-1)*d(n)):
    seq(seq(A(n, h-n), n=0..h), h=0..14);

Formula

A(n,k) = A258851(n^k) = k * n^(k-1) * A258851(n).

A230540 a(n) = 2*n*3^(2*n-1).

Original entry on oeis.org

0, 6, 108, 1458, 17496, 196830, 2125764, 22320522, 229582512, 2324522934, 23245229340, 230127770466, 2259436291848, 22029503845518, 213516729579636, 2058911320946490, 19765548681086304, 189008059262887782, 1801135623563989452, 17110788423857899794
Offset: 0

Views

Author

Bruno Berselli, Oct 23 2013

Keywords

Comments

Arithmetic derivative of 9^n: a(n) = A003415(9^n).
Sum of reciprocals of a(n), for n>0: (3/2)*log(9/8).

Crossrefs

Cf. arithmetic derivative of k^n: A001787 (k=2), A027471 (k=3), A018215 (k=4), A053464 (k=5), A212700 (k=6), A027473 (k=7), A230539 (k=8), this sequence, A085708 (k=10), A081127 (k=11).

Programs

  • Magma
    [2*n*3^(2*n-1): n in [0..20]];
    
  • Mathematica
    Table[2 n 3^(2 n - 1), {n, 0, 20}]
  • PARI
    a(n) = 2*n*3^(2*n-1); \\ Michel Marcus, Oct 23 2013

Formula

G.f.: 6*x/(1-9*x)^2.
a(n) = 6*A053540(n), with A053540(0)=0.
Showing 1-2 of 2 results.