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A163676
Triangle T(n,m) = 4mn + 2m + 2n - 1 read by rows.
2
7, 13, 23, 19, 33, 47, 25, 43, 61, 79, 31, 53, 75, 97, 119, 37, 63, 89, 115, 141, 167, 43, 73, 103, 133, 163, 193, 223, 49, 83, 117, 151, 185, 219, 253, 287, 55, 93, 131, 169, 207, 245, 283, 321, 359, 61, 103, 145, 187, 229, 271, 313, 355, 397, 439, 67, 113, 159
OFFSET
1,1
COMMENTS
2 + T(n,m) = (2*n+1)*(2*m+1) are composite numbers. - clarified by R. J. Mathar, Oct 16 2009
First column: A016921, second column: A017305, third column: A126980. - Vincenzo Librandi, Nov 21 2012
LINKS
Vincenzo Librandi, Rows n = 1..100, flattened
FORMULA
T(n,m) = A155151(n,m) - 3 = A155156(n,m) - 1. - R. J. Mathar, Oct 16 2009
EXAMPLE
Triangle begins:
7;
13, 23;
19, 33, 47;
25, 43, 61, 79;
31, 53, 75, 97, 119;
37, 63, 89, 115, 141, 167;
43, 73, 103, 133, 163, 193, 223;
49, 83, 117, 151, 185, 219, 253, 287;
55, 93, 131, 169, 207, 245, 283, 321, 359;
61, 103, 145, 187, 229, 271, 313, 355, 397, 439;
MATHEMATICA
t[n_, k_]:=4 n*k + 2n + 2k - 1; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 21 2012 *)
PROG
(Magma) [4*n*k + 2*n + 2*k - 1: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 21 2012
(PARI) for(n=1, 10, for(k=1, n, print1(4*n*k + 2*n + 2*k - 1, ", "))) \\ G. C. Greubel, Aug 02 2017
CROSSREFS
KEYWORD
nonn,easy,tabl
AUTHOR
Vincenzo Librandi, Aug 03 2009
STATUS
approved