A111848
Matrix log of triangle A111845, which shifts columns left and up under matrix 4th power; these terms are the result of multiplying each element in row n and column k by (n-k)!.
Original entry on oeis.org
0, 1, 0, 4, 4, 0, 56, 16, 16, 0, 1728, 224, 64, 64, 0, -45696, 6912, 896, 256, 256, 0, -159401472, -182784, 27648, 3584, 1024, 1024, 0, 387212983296, -637605888, -731136, 110592, 14336, 4096, 4096, 0, 14722642769657856, 1548851933184, -2550423552, -2924544, 442368, 57344, 16384, 16384, 0
Offset: 0
Matrix log of A111845, with factorial denominators, begins:
0;
1/1!, 0;
4/2!, 4/1!, 0;
56/3!, 16/2!, 16/1!, 0;
1728/4!, 224/3!, 64/2!, 64/1!, 0;
-45696/5!, 6912/4!, 896/3!, 256/2!, 256/1!, 0; ...
A111845
Triangle P, read by rows, that satisfies [P^4](n,k) = P(n+1,k+1) for n>=k>=0, also [P^(4*m)](n,k) = [P^m](n+1,k+1) for all m, where [P^m](n,k) denotes the element at row n, column k, of the matrix power m of P, with P(k,k)=1 and P(k+1,1)=P(k+1,0) for k>=0.
Original entry on oeis.org
1, 1, 1, 4, 4, 1, 40, 40, 16, 1, 1040, 1040, 544, 64, 1, 78240, 78240, 48960, 8320, 256, 1, 18504256, 18504256, 13110400, 2878720, 131584, 1024, 1, 14463224448, 14463224448, 11192599808, 2982187520, 180270080, 2099200, 4096, 1
Offset: 0
Let q=4; the g.f. of column k of matrix power P^m is:
1 + (m*q^k)*L(x) + (m*q^k)^2/2!*L(x)*L(q*x) +
(m*q^k)^3/3!*L(x)*L(q*x)*L(q^2*x) +
(m*q^k)^4/4!*L(x)*L(q*x)*L(q^2*x)*L(q^3*x) + ...
where L(x) satisfies:
x = L(x) - L(x)*L(q*x)/2! + L(x)*L(q*x)*L(q^2*x)/3! +- ...
and L(x) = x + 4/2!*x^2 + 56/3!*x^3 + 1728/4!*x^4 + ... (A111849).
Thus the g.f. of column 0 of matrix power P^m is:
1 + m*L(x) + m^2/2!*L(x)*L(4*x) + m^3/3!*L(x)*L(4*x)*L(4^2*x) +
m^4/4!*L(x)*L(4*x)*L(4^2*x)*L(4^3*x) + ...
Triangle P begins:
1;
1,1;
4,4,1;
40,40,16,1;
1040,1040,544,64,1;
78240,78240,48960,8320,256,1;
18504256,18504256,13110400,2878720,131584,1024,1; ...
where P^4 shifts columns left and up one place:
1;
4,1;
40,16,1;
1040,544,64,1;
78240,48960,8320,256,1; ...
-
{P(n,k,q=4) = my(A=Mat(1),B);if(nPaul D. Hanna, Jul 11 2025):
for(n=0,10, for(k=0,n, print1(P(n,k),", ")); print(""))
A111846
Number of partitions of 4^n - 1 into powers of 4, also equals column 0 of triangle A111845, which shifts columns left and up under matrix 4th power.
Original entry on oeis.org
1, 1, 4, 40, 1040, 78240, 18504256, 14463224448, 38544653734144, 357896006503348736, 11766320092785122862080, 1387031702368547767793690624, 592262859312707222259571097997312
Offset: 0
G.f. A(x) = 1 + L(x) + L(x)*L(4*x)/2! + L(x)*L(4*x)*L(4^2*x)/3!
+ L(x)*L(4*x)*L(4^2*x)*L(4^3*x)/4! + ...
where L(x) satisfies:
x = L(x) - L(x)*L(4*x)/2! + L(x)*L(4*x)*L(4^2*x)/3! +- ...
and L(x) = x + 4/2!*x^2 + 56/3!*x^3 + 1728/4!*x^4 +....(A111849).
-
{a(n,q=4)=local(A=Mat(1),B);if(n<0,0, for(m=1,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=1,if(j==1,B[i,j]=(A^q)[i-1,1], B[i,j]=(A^q)[i-1,j-1]));));A=B);return(A[n+1,1]))}
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