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A223524
Triangle S(n, k) by rows: coefficients of 2^(n/2)*(x^(1/2)*d/dx)^n, where n =0, 2, 4, 6, ...
0
1, 1, 2, 3, 12, 4, 15, 90, 60, 8, 105, 840, 840, 224, 16, 945, 9450, 12600, 5040, 720, 32, 10395, 124740, 207900, 110880, 23760, 2112, 64, 135135, 1891890, 3783780, 2522520, 720720, 96096, 5824, 128, 2027025, 32432400
OFFSET
1,3
EXAMPLE
Triangle begins:
1;
1, 2;
3, 12, 4;
15, 90, 60, 8;
105, 840, 840, 224, 16;
945, 9450, 12600, 5040, 720, 32;
10395, 124740, 207900, 110880, 23760, 2112, 64;
.
.
Expansion takes the form:
2^1 (x^(1/2)*d/dx)^2 = 1*d/dx + 2*x*d^2/dx^2.
2^2 (x^(1/2)*d/dx)^4 = 3*d^2/dx^2 + 12*x*d^3/dx^3 + 4*x^2*d^4/dx^4.
MAPLE
a[0]:= f(x):
for i from 1 to 20 do
a[i]:= simplify(2^((i+1)mod 2)*x^(1/2)*(diff(a[i-1], x$1)));
end do:
for j from 1 to 10 do
b[j]:=a[2j];
end do;
CROSSREFS
Rows includes even rows of A223168.
Sequence in context: A288330 A162846 A072734 * A046207 A030611 A252177
KEYWORD
nonn,tabl
AUTHOR
Udita Katugampola, Mar 21 2013
STATUS
approved