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A243868 0 followed by -(n+1)*A226158(n). 0
0, 0, 2, 3, 0, -5, 0, 21, 0, -153, 0, 1705, 0, -26949, 0, 573405, 0, -15802673, 0, 547591761, 0, -23302711005, 0, 1194695479813, 0, -72628776062025, 0, 5165901157067001, 0, -425013158488292213, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

An autosequence is a sequence which has its inverse binomial transform equal to the signed sequence. If the main diagonal is A000004=0's it is of the first kind. It is of the second kind if the main diagonal is the upper diagonal multiplied by 2.

Starting from the autosequence of second kind A198631(n)/A006519(n+1),the fractional Euler numbers,we build a family of alternated sequences of second and first kind. A row is 0 followed by n+1 times the preceding one.

1, 1/2, 0, -1/4,  0, 1/2, 0, -17/8,   0, 31/2,...

0,   1, 1,    0, -1,   0, 3,     0, -17,    0, 155,... = -A226158(n)

0,   0, 2,    3,  0,  -5, 0,    21,   0, -153, 0, 1705,... = a(n).

a(n) is an autosequence of the second kind. Its difference table is:

0,     0,   2,   3,   0,  -5,   0,  21, 0, -153,...

0,     2,   1,  -3,  -5,   5,  21, -21,...

2,    -1,  -4,  -2,  10,  16, -42,...

-3,   -3,   2,  12,   6, -58,..

0,     5,  10,  -6, -64,...

5,     5, -16, -58,...

0,   -21, -42,...

-21, -21,...

0,... .

a(n) is a post Genocchi sequence.

LINKS

Table of n, a(n) for n=0..30.

FORMULA

The fourth column of the second triangle of A133135(n) (see also A140218) is

1, -5/2, 5/2, 0, 0, -21/2, 21/2,... = b(n).

c(n) = 0, 0, 0, 0, followed by 2*(-1)^n*b(n) = 0, 0, 0, 0, 2, 5, 5, 0, 0, 21, 21, -132, -132,... . Autosequence.

a(n) = c(n+2) -c(n+1).

EXAMPLE

a(0)=0, a(1)=1*0=0, a(2)=2*1=2, a(3)=3*1=3, a(4)=4*0=0, a(5)=5*(-1)=-5.

MATHEMATICA

a[0] = a[1] = 0; a[2] = 2; a[n_] := -n*(n-1)*EulerE[n-2, 0]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jun 17 2014 *)

CROSSREFS

Cf. A102055, A230011, A229054.

Sequence in context: A064502 A082809 A070245 * A066398 A138197 A140664

Adjacent sequences:  A243865 A243866 A243867 * A243869 A243870 A243871

KEYWORD

sign,frac,tabl

AUTHOR

Paul Curtz, Jun 13 2014

EXTENSIONS

More terms from Jean-François Alcover, Jun 17 2014

STATUS

approved

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Last modified April 25 14:25 EDT 2015. Contains 257073 sequences.