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A060237
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n!^2 *(sum{m=1 to n} sum{k=1 to m}[1/(k m)]).
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1
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1, 7, 85, 1660, 48076, 1942416, 104587344, 7245893376, 628308907776, 66687811660800, 8506654697548800, 1284292319599411200, 226530955276874956800, 46165213716463676620800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a[n] = a[n-1] *n^2 + (n-1)! *n! *(sum{k=1 to n}[1/k])
Sum_{n>=0} a(n)*x^n/n!^2 = -dilog(1/(1-x))/(1-x). a(n) = n!^2*Sum_{k=1..n} (-1)^(k+1)*binomial(n, k)/k^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 29 2005
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EXAMPLE
| a(2) = 2!^2 *(1/(1*1) + 1/(1*2) + 1/(2*2)) = 7.
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CROSSREFS
| Essentially the same as A000424.
Sequence in context: A056547 A121020 A000424 * A000686 A102923 A196257
Adjacent sequences: A060234 A060235 A060236 * A060238 A060239 A060240
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KEYWORD
| easy,nonn
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AUTHOR
| Leroy Quet Mar 21 2001
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