|
|
A002435
|
|
Second-order Euler numbers.
(Formerly M1686 N0665)
|
|
0
|
|
|
0, 2, 6, 28, 180, 662, 7266, 24568, 408360, 1326122, 30974526, 98329108, 3065784540, 9596075582, 384653685786, 1192744081648, 59724464976720, 183983154281042, 11249503075325046, 34489251602450188
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
REFERENCES
|
A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 75.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
|
|
LINKS
|
|
|
MAPLE
|
F := 2/(exp(x)+exp(-x)): z := ((exp(x)-exp(-x))/(exp(x)+exp(-x)))^2: w := simplify(diff(z, x)): p := proc(n) if n mod 2 = 0 then simplify(subs(x=0, (-1)^(1+floor(n/2))*simplify(diff(diff(F, x$n)/F, x)/w))) else simplify(subs(x=0, (-1)^(1+floor(n/2))*simplify(diff(diff(F, x$n)/simplify(diff(F, x)), x)/w))) fi end: seq(p(n), n=1..28); # Emeric Deutsch, Mar 09 2004
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|