A154681 Triangle read by rows where T(m,n) = 2*m*n + m + n +3.

7, 10, 15, 13, 20, 27, 16, 25, 34, 43, 19, 30, 41, 52, 63, 22, 35, 48, 61, 74, 87, 25, 40, 55, 70, 85, 100, 115, 28, 45, 62, 79, 96, 113, 130, 147, 31, 50, 69, 88, 107, 126, 145, 164, 183, 34, 55, 76, 97, 118, 139, 160, 181, 202, 223, 37, 60, 83, 106, 129, 152

Offset

1,1

Comments

2*T(m,n) - 5 = (2*n+1)*(2*m+1) is not prime.

First column: A112414; second column: A008587.

Links

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

Example

Triangle begins:
  7;
  10, 15;
  13, 20, 27;
  16, 25, 34, 43;
  19, 30, 41, 52,  63;
  22, 35, 48, 61,  74,  87;
  25, 40, 55, 70,  85, 100, 115;
  28, 45, 62, 79,  96, 113, 130, 147;
  31, 50, 69, 88, 107, 126, 145, 164, 183;
  34, 55, 76, 97, 118, 139, 160, 181, 202, 223; etc.

Mathematica

t[n_, k_]:=2 n*k + n + k + 3; Table[t[n, k], {n, 10}, {k, n}]//Flatten (* _vincenzo Librandi_, Nov 17 2012 *)

Prog

(Magma) [(2*n*k + n + k + 3): k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 17 2012

Crossrefs

Cf. A153040, A008587, A089253, A112414.

Sequence in context: A020721 A015782 A336089 * A225676 A030764 A155716

Adjacent sequences: A154678 A154679 A154680 * A154682 A154683 A154684

Keyword

nonn,tabl,easy

Author

Vincenzo Librandi, Jan 18 2009

Status

approved