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.

A276586 Square array A(row,col) = Sum_{k=0..row} binomial(row,k)*A002110(col+k), read by descending antidiagonals as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

1, 2, 3, 6, 8, 11, 30, 36, 44, 55, 210, 240, 276, 320, 375, 2310, 2520, 2760, 3036, 3356, 3731, 30030, 32340, 34860, 37620, 40656, 44012, 47743, 510510, 540540, 572880, 607740, 645360, 686016, 730028, 777771, 9699690, 10210200, 10750740, 11323620, 11931360, 12576720, 13262736, 13992764, 14770535
Offset: 0

Views

Author

Antti Karttunen, Sep 18 2016

Keywords

Examples

			The top left corner of the array:
     1,     2,      6,       30,       210,       2310,        30030
     3,     8,     36,      240,      2520,      32340,       540540
    11,    44,    276,     2760,     34860,     572880,     10750740
    55,   320,   3036,    37620,    607740,   11323620,    253753500
   375,  3356,  40656,   645360,  11931360,  265077120,   7422334920
  3731, 44012, 686016, 12576720, 277008480, 7687412040, 235239464460
		

Crossrefs

Transpose: A276587.
Topmost row: A002110, Leftmost column: A136104.
Cf. also arrays A066117, A276588, A099884, A255483.

Programs

  • Mathematica
    primorial[n_] := Product[Prime[k], {k, 1, n}]; A[n_, k_] := Sum[Binomial[n, j]*primorial[k+j], {j, 0, n}]; Table[A[n-k, k], {n, 0, 9}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Jan 22 2017 *)
  • PARI
    P(n)=prod(i=1, n, prime(i));
    T(n, k) = sum(j=0, n, binomial(n, j)*P(k + j));
    for(n=0, 10, for(k=0, n, print1(T(k, n - k),", ");); print();) \\ Indranil Ghosh, Apr 11 2017
  • Scheme
    (define (A276586 n) (A276586bi (A002262 n) (A025581 n)))
    (define (A276586bi row col) (A276085 (A066117bi (+ 1 row) (+ 1 col))))
    

Formula

A(row,col) = Sum_{k=0..row} binomial(row,k)*A002110(col+k).
A(row,col) = A276085(A066117(row+1,col+1)).