A154614 Triangle read by rows where T(m,n) = m*n + m + n - 1, 1<=n<=m.

2, 4, 7, 6, 10, 14, 8, 13, 18, 23, 10, 16, 22, 28, 34, 12, 19, 26, 33, 40, 47, 14, 22, 30, 38, 46, 54, 62, 16, 25, 34, 43, 52, 61, 70, 79, 18, 28, 38, 48, 58, 68, 78, 88, 98, 20, 31, 42, 53, 64, 75, 86, 97, 108, 119, 22, 34, 46, 58, 70, 82, 94, 106, 118, 130, 142

Offset

1,1

Comments

T(m,n)+2 = (n+1)*(m+1) is not prime.

T(m,m)+2 = (m+1)^2.

First column: A005843; second column: A112414; third column: 2*A020742; fourth column: A016885. - Vincenzo Librandi, Nov 17 2012

Links

Vincenzo Librandi, Rows n = 1..100, flattened

Example

Triangle begins:
2;
4, 7;
6, 10, 14;
8, 13, 18, 23;
10, 16, 22, 28, 34;
12, 19, 26, 33, 40, 47;
14, 22, 30, 38, 46, 54, 62;
16, 25, 34, 43, 52, 61, 70, 79;
18, 28, 38, 48, 58, 68, 78, 88, 98;
20, 31, 42, 53, 64, 75, 86, 97, 108, 119; etc.

Mathematica

t[n_, k_]:=n*k + n + k - 1; Table[t[n, k], {n, 10}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 17 2012 *)

Prog

(Magma) [(n*k + n + k - 1): k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 17 2012

Crossrefs

Cf. A040976, A005843, A112414, A020742, A016885.

Sequence in context: A129980 A198137 A126786 * A342616 A161211 A276807

Adjacent sequences: A154611 A154612 A154613 * A154615 A154616 A154617

Keyword

nonn,easy,tabl

Author

Vincenzo Librandi, Jan 16 2009

Status

approved