A153144
Numbers n such that 2*n+19 is not a prime.
Original entry on oeis.org
1, 3, 4, 7, 8, 10, 13, 15, 16, 18, 19, 22, 23, 25, 28, 29, 31, 33, 34, 36, 37, 38, 40, 43, 46, 48, 49, 50, 51, 52, 53, 55, 57, 58, 61, 62, 63, 64, 67, 68, 70, 71, 73, 75, 76, 78, 79, 82, 83, 84, 85, 88, 91, 92, 93, 94, 95, 97, 98, 99, 100, 101
Offset: 1
A154680
Triangle read by rows where T(m,n)=2*m*n + m + n - 2.
Original entry on oeis.org
2, 5, 10, 8, 15, 22, 11, 20, 29, 38, 14, 25, 36, 47, 58, 17, 30, 43, 56, 69, 82, 20, 35, 50, 65, 80, 95, 110, 23, 40, 57, 74, 91, 108, 125, 142, 26, 45, 64, 83, 102, 121, 140, 159, 178, 29, 50, 71, 92, 113, 134, 155, 176, 197, 218, 32, 55, 78, 101, 124, 147, 170, 193, 216, 239, 262
Offset: 1
Triangle begins:
2;
5, 10;
8, 15, 22;
11, 20, 29, 38;
14, 25, 36, 47, 58;
17, 30, 43, 56, 69, 82;
20, 35, 50, 65, 80, 95, 110;
23, 40, 57, 74, 91, 108, 125, 142;
26, 45, 64, 83, 102, 121, 140, 159, 178;
29, 50, 71, 92, 113, 134, 155, 176, 197, 218; etc.
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[2*n*k+n+k-2: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 18 2012
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Flatten[Table[Floor[2 n m + m + n - 2], {n, 1, 16}, {m, n}]] (* Vincenzo Librandi, May 14 2012 *)
A155723
Numbers k such that 2*k + 9 is not prime.
Original entry on oeis.org
0, 3, 6, 8, 9, 12, 13, 15, 18, 20, 21, 23, 24, 27, 28, 30, 33, 34, 36, 38, 39, 41, 42, 43, 45, 48, 51, 53, 54, 55, 56, 57, 58, 60, 62, 63, 66, 67, 68, 69, 72, 73, 75, 76, 78, 80, 81, 83, 84, 87, 88, 89, 90, 93, 96, 97, 98, 99, 100, 102, 103, 104, 105, 106, 108, 111, 113, 114
Offset: 1
Distribution of the terms in the following triangular array:
0;
3, 8;
6, 13, 20;
9, 18, 27, 36;
12, 23, 34, 45, 56;
15, 28, 41, 54, 67, 80;
18, 33, 48, 63, 78, 93, 108;
21, 38, 55, 72, 89, 106, 123, 140;
24, 43, 62, 81, 100, 119, 138, 157, 176;
27, 48, 69, 90, 111, 132, 153, 174, 195, 216;
30, 53, 76, 99, 122, 145, 168, 191, 214, 237, 260;
33, 58, 83, 108, 133, 158, 183, 208, 233, 258, 283, 308;
36, 63, 90, 117, 144, 171, 198, 225, 252, 279, 306, 333, 360;
etc.
the values of (2*h*k + k + h - 4) with h >= k >= 1. - _Vincenzo Librandi_, Jan 16 2013
Showing 1-3 of 3 results.
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