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A144670 Triangle read by rows where T(m,n)=2mn+m+n-7 3

%I #8 Sep 08 2022 08:45:38

%S -3,0,5,3,10,17,6,15,24,33,9,20,31,42,53,12,25,38,51,64,77,15,30,45,

%T 60,75,90,105,18,35,52,69,86,103,120,137,21,40,59,78,97,116,135,154,

%U 173,24,45,66,87,108,129,150,171,192,213,27,50,73,96,119,142,165,188,211,234,257

%N Triangle read by rows where T(m,n)=2mn+m+n-7

%C Numbers n such that, if 2^(s-1)=n then [A144487] is not prime.

%C Let p (prime number), n=(p^2-15)/2 mod(p).

%H Vincenzo Librandi, <a href="/A144670/b144670.txt">Rows n = 100, flattened</a>

%e Triangle begins:

%e -3;

%e 0, 5;

%e 3, 10, 17;

%e 6, 15, 24, 33;

%e 9, 20, 31, 42, 53;

%e 12, 25, 38, 51, 64, 77;

%e 15, 30, 45, 60, 75, 90, 105;

%e 18, 35, 52, 69, 86, 103, 120, 137;

%e 21, 40, 59, 78, 97, 116, 135, 154, 173;

%e 24, 45, 66, 87, 108, 129, 150, 171, 192, 213;

%e = = = = = = = =

%t t[n_,k_]:=2 n*k+n+k-7; Table[t[n, k], {n, 12}, {k, n}] // Flatten (* _Vincenzo Librandi_, Oct 15 2012 *)

%o (Magma) [2*n*k + n + k -7: k in [1..n], n in [1..12]]; // _Vincenzo Librandi_, Oct 15 2012

%Y Cf. A057197, A144487.

%K tabl,sign

%O 1,1

%A _Vincenzo Librandi_, Jan 28 2009

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Last modified April 25 09:38 EDT 2024. Contains 371967 sequences. (Running on oeis4.)