A173043 - OEIS

%I #7 Feb 19 2021 18:34:28

%S 1,1,1,1,5,1,1,10,10,1,1,19,261,19,1,1,36,32777,32777,36,1,1,69,

%T 16777230,68719476755,16777230,69,1,1,134,34359738388,

%U 1180591620717411303458,1180591620717411303458,34359738388,134,1

%N Triangle T(n, k, q) = binomial(n, k) - 1 + q^(n*binomial(n-2, k-1)) with T(n, 0, q) = T(n, n, q) = 1 and q = 2, read by rows.

%H G. C. Greubel, <a href="/A173043/b173043.txt">Rows n = 0..12 of the triangle, flattened</a>

%F T(n, k, q) = binomial(n, k) - 1 + q^(n*binomial(n-2, k-1)) with T(n, 0, q) = T(n, n, q) = 1 and q = 2.

%F Sum_{k=0..n} T(n, k, 2) = A000295(n) + Sum_{k=0..n} 2^(n*binomial(n-2, k-1)). - _G. C. Greubel_, Feb 19 2021

%e Triangle begins as:

%e   1;

%e   1,  1;

%e   1,  5,        1;

%e   1, 10,       10,           1;

%e   1, 19,      261,          19,        1;

%e   1, 36,    32777,       32777,       36,  1;

%e   1, 69, 16777230, 68719476755, 16777230, 69, 1;

%t T[n_, k_, q_]:= If[k==0 || k==n, 1, Binomial[n, k] - 1 + q^(n*Binomial[n-2, k-1])];

%t Table[t[n, k, 2], {n,0,12}, {k,0,n}]//Flatten (* modified by _G. C. Greubel_, Feb 19 2021 *)

%o (Sage)

%o def T(n,k,q):

%o     if (k==0 or k==n): return 1

%o     else: return binomial(n,k) -1 +q^(n*binomial(n-2, k-1))

%o flatten([[T(n,k,2) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Feb 19 2021

%o (Magma)

%o T:= func< n,k,q | k eq 0 or k eq n select 1 else Binomial(n,k) -1 +q^(n*Binomial(n-2, k-1)) >;

%o [T(n,k,2): k in [0..n], n in [0..12]]; // _G. C. Greubel_, Feb 19 2021

%Y Cf. A132044 (q=0), A007318 (q=1), this sequence (q=2), A173045 (q=3).

%Y Cf. A000295.

%K nonn,tabl

%O 0,5

%A _Roger L. Bagula_, Feb 08 2010

%E Edited by _G. C. Greubel_, Feb 19 2021