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A223168 Triangle S(n, k) by rows: coefficients of 2^((n-1)/2))*(x^(1/2)*d/dx)^n when n is odd, and of 2^(n/2)*(x^(1/2)*d/dx)^n when n is even. 32
1, 1, 2, 3, 2, 3, 12, 4, 15, 20, 4, 15, 90, 60, 8, 105, 210, 84, 8, 105, 840, 840, 224, 16, 945, 2520, 1512, 288, 16, 945, 9450, 12600, 5040, 720, 32, 10395, 34650, 27720, 7920, 880, 32, 10395, 124740, 207900, 110880, 23760, 2112, 64, 135135, 540540, 540540, 205920, 34320, 2496, 64 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also coefficients in the expansion of k-th derivative of exp(n*x^2), see Mathematica program. - Vaclav Kotesovec, Jul 16 2013

LINKS

Vincenzo Librandi, Rows n = 0..60, flattened

EXAMPLE

Triangle begins:

1;

1, 2;

3, 2;

3, 12, 4;

15, 20, 4;

15, 90, 60, 8;

105, 210, 84, 8;

105, 840, 840, 224, 16;

945, 2520, 1512, 288, 16;

945, 9450, 12600, 5040, 720, 32;

10395, 34650, 27720, 7920, 880, 32;

10395, 124740, 207900, 110880, 23760, 2112, 64;

135135, 540540, 540540, 205920, 34320, 2496, 64;

.

.

Expansion takes the form:

2^0 (x^(1/2)*d/dx)^1 = 1*x^(1/2)*d/dx.

2^1 (x^(1/2)*d/dx)^2 = 1*d/dx + 2*x*d^2/dx^2.

2^1 (x^(1/2)*d/dx)^3 = 3*x^(1/2)*d^2/dx^2 + 2*x^(3/2)*d^3/dx^3.

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.

2^2 (x^(1/2)*d/dx)^5 = 15*x^(1/2)*d^3/dx^3 + 20*x^(3/2)*d^4/dx^4 + 4*x^(5/2)*d^5/dx^5.

`

`

MAPLE

a[0]:= f(x);

for i from 1 to 13 do

a[i]:= simplify(2^((i+1)mod 2)*x^(1/2)*(diff(a[i-1], x$1)));

end do;

MATHEMATICA

Flatten[CoefficientList[Expand[FullSimplify[Table[D[E^(n*x^2), {x, k}]/(E^(n*x^2)*(2*n)^Floor[(k+1)/2]), {k, 1, 13}]]]/.x->1, n]] (* Vaclav Kotesovec, Jul 16 2013 *)

CROSSREFS

Odd rows includes absolute values of A098503 from right to left.

Cf. A223169-A223172, A223523-A223532, A008277, A019538, A035342, A035469, A049029, A049385, A092082, A132056, A223511-A223522.

Sequence in context: A093868 A194603 A183465 * A077942 A077989 A109620

Adjacent sequences:  A223165 A223166 A223167 * A223169 A223170 A223171

KEYWORD

nonn,tabf

AUTHOR

Udita Katugampola, Mar 17 2013

STATUS

approved

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Last modified April 24 14:19 EDT 2014. Contains 240985 sequences.