A079783 Sum of n-th row of triangle in A079784.

2, 9, 30, 38, 285, 339, 2912, 6684, 22635, 25145, 304854, 332562, 4684589, 5044935, 5405280, 11531384, 208287927, 220540149, 4423058450, 4655850990, 4888643529, 5121436067, 123147263964, 128501492820, 669278609675, 696049754049, 2168462696022, 2248776129194

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Formula

a(n) = n*[A079782(n)-(n-1)/2]. - R. J. Mathar, Nov 12 2006

Example

The fifth row 55,56,57,58,59 is divisible by 5,4,3,2 and 1 respectively.

Mathematica

a[n_] := n*(Which[n == 1, 2, n == 2, 5, n == 3, 11, True, LCM @@ Range[n] - 1] - (n-1)/2);
Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Jun 17 2024 *)

Prog

(PARI) okrow(m, n) = {v = vector(n, i, i+m-1); for (i=1, n, if (v[i] % (n-i+1), return (0)); ); return (1); }
a(n) =  {m = n+1; while (! okrow(m, n), m++); sum(k=1, n, m+k-1); } \\ Michel Marcus, Feb 28 2014

Crossrefs

Cf. A079781, A079782, A079784.

Sequence in context: A150904 A122675 A042357 * A182975 A228932 A196421

Adjacent sequences: A079780 A079781 A079782 * A079784 A079785 A079786

Keyword

nonn

Author

Amarnath Murthy, Feb 03 2003

Extensions

More terms from Michel Marcus, Feb 28 2014

Status

approved