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A155546
Triangle read by rows where T(m,n)=2mn + m + n - 5, 1<=n<=m.
5
-1, 2, 7, 5, 12, 19, 8, 17, 26, 35, 11, 22, 33, 44, 55, 14, 27, 40, 53, 66, 79, 17, 32, 47, 62, 77, 92, 107, 20, 37, 54, 71, 88, 105, 122, 139, 23, 42, 61, 80, 99, 118, 137, 156, 175, 26, 47, 68, 89, 110, 131, 152, 173, 194, 215, 29, 52, 75, 98, 121, 144, 167, 190, 213
OFFSET
1,2
COMMENTS
2*T(m,n)+11 = (2*m+1)*(2*n+1) is not prime.
First column: A016789, second column: A016873, third column: A017041, fourth column: A017257. - Vincenzo Librandi, Nov 21 2012
LINKS
Vincenzo Librandi, Rows n = 1..100, flattened
EXAMPLE
Triangle begins:
-1;
2, 7;
5, 12, 19;
8, 17, 26, 35;
11, 22, 33, 44, 55;
14, 27, 40, 53, 66, 79;
17, 32, 47, 62, 77, 92, 107;
20, 37, 54, 71, 88, 105, 122, 139;
23, 42, 61, 80, 99, 118, 137, 156, 175;
26, 47, 68, 89, 110, 131, 152, 173, 194, 215; etc.
MATHEMATICA
t[n_, k_]:= 2 n*k + n + k - 5; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 21 2012 *)
PROG
(Magma) [2*n*k + n + k - 5: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 21 2012
CROSSREFS
KEYWORD
tabl,sign,easy
AUTHOR
Vincenzo Librandi, Jan 24 2009
STATUS
approved