This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A134319 #25 Jun 23 2023 10:31:44
%S A134319 1,1,1,1,2,3,1,3,9,7,1,4,18,28,15,1,5,30,70,75,31,1,6,45,140,225,186,
%T A134319 63,1,7,63,245,525,651,441,127,1,8,84,392,1050,1736,1764,1016,255,1,9,
%U A134319 108,588,1890,3906,5292,4572,2295,511,1,10,135,840,3150,7812,13230,15240,11475,5110,1023
%N A134319 Triangle read by rows. T(n, k) = binomial(n, k)*(2^k - 1 + 0^k).
%H A134319 Alois P. Heinz, <a href="/A134319/b134319.txt">Rows n = 0..140, flattened</a>
%F A134319 Previous definition: A007318 * a triangle by rows: for n > 0, n zeros followed by 2^n - 1.
%F A134319 Binomial transform of a diagonalized infinite lower triangular matrix with (1, 1, 3, 7, 15, ...) in the main diagonal and the rest zeros.
%F A134319 T(n,k) = |[1/(2^x)^k] 1 + (1-1/2^x)^n - (1-2/2^x)^n|. - _Alois P. Heinz_, Dec 10 2008
%F A134319 T(n,k) = binomial(n,k)*M(k) where M is Mersenne-like A255047. - _Yuchun Ji_, Feb 13 2019
%e A134319 First few rows of the triangle:
%e A134319 1;
%e A134319 1, 1;
%e A134319 1, 2, 3;
%e A134319 1, 3, 9, 7;
%e A134319 1, 4, 18, 28, 15;
%e A134319 1, 5, 30, 70, 75, 31;
%e A134319 1, 6, 45, 140, 225, 186, 63;
%e A134319 1, 7, 63, 245, 525, 651, 441, 127;
%e A134319 ...
%p A134319 x:= 'x': T:= (n,k)-> `if` (k=0, 1, abs(coeff(expand((1-1/2^x)^n -(1-2/2^x)^n), 1/(2^x)^k))): seq(seq(T(n,k), k=0..n), n=0..12); # _Alois P. Heinz_, Dec 10 2008
%p A134319 # Alternative:
%p A134319 T := (n, k) -> binomial(n, k)*(2^k - 1 + 0^k):
%p A134319 for n from 0 to 7 do seq(T(n, k), k=0..n) od;
%p A134319 # Or as a recursion:
%p A134319 p := proc(n, m) option remember; if n = 0 then max(1, m) else
%p A134319 (m + x)*p(n - 1, m) - (m + 1)*p(n - 1, m + 1) fi end:
%p A134319 Trow := n -> seq((-1)^k * coeff(p(n, 0), x, n - k), k = 0..n): # _Peter Luschny_, Jun 23 2023
%t A134319 max = 10; T1 = Table[Binomial[n, k], {n, 0, max}, {k, 0, max}]; T2 = Table[ If[n == k, 2^n-1, 0], {n, 0, max}, {k, 0, max}]; TT = T1.T2 ; T[_, 0]=1; T[n_, k_] := TT[[n+1, k+1]]; Table[T[n, k], {n, 0, max}, {k, 0, n}] // Flatten (* _Jean-François Alcover_, May 26 2016 *)
%Y A134319 Cf. A083313, A083323 (row sums), A255047 (main diagonal).
%K A134319 nonn,tabl
%O A134319 0,5
%A A134319 _Gary W. Adamson_, Oct 19 2007
%E A134319 More terms from _Alois P. Heinz_, Dec 10 2008
%E A134319 New name using a formula of _Yuchun Ji_ by _Peter Luschny_, Jun 23 2023