A155550 Triangle read by rows where T(m,n)=2*m*n + m + n - 6.

-2, 1, 6, 4, 11, 18, 7, 16, 25, 34, 10, 21, 32, 43, 54, 13, 26, 39, 52, 65, 78, 16, 31, 46, 61, 76, 91, 106, 19, 36, 53, 70, 87, 104, 121, 138, 22, 41, 60, 79, 98, 117, 136, 155, 174, 25, 46, 67, 88, 109, 130, 151, 172, 193, 214, 28, 51, 74, 97, 120, 143, 166, 189, 212

Offset: 1

Author

Vincenzo Librandi, Jan 24 2009

Keywords

• tabl
• sign

Comments

Numbers n such that 2n+13 is not prime.

First column: A016777, second column: A016861, third column: A017029, fourth column: A017245. - Vincenzo Librandi, Nov 21 2012

Examples

			Triangle begins:
-2;
1,  6;
4,  11, 18;
7,  16, 25, 34;
10, 21, 32, 43, 54;
13, 26, 39, 52, 65,  78;
16, 31, 46, 61, 76,  91,  106;
19, 36, 53, 70, 87,  104, 121, 138;
22, 41, 60, 79, 98,  117, 136, 155, 174;
25, 46, 67, 88, 109, 130, 151, 172, 193, 214; etc.
		

Links

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

Crossrefs

Cf. A153082, A016777, A016861, A017029, A017245.

Programs

Magma

[2*n*k + n + k - 6: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 21 2012

Mathematica

t[n_,k_]:= 2 n*k + n + k - 6; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 21 2012 *)