need help for function
Max
relf at unn.ac.ru
Wed Feb 16 11:01:46 CET 2005
Oh, it's even simpler ;)
{ a(n) = sum(k=1,n,(n+1-k)*d2(k)) }
Max
Max wrote:
> Directly in Pari code:
>
> { d2(n) = if(n%2,n!,n!-(n/2)!) }
>
> { a(n) = 2*n - 1 + sum(k=3,n,(n+1-k)*d2(k)) }
>
> Max
>
> Eugene McDonnell wrote:
>
>> I have a sequence:
>>
>> n 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
>> a(n) 1 3 11 41 191 1055 6959 53159 462239 4499999 48454559 571409999
>> 7321386239 101249648639 1502852279039
>>
>> where the second differences d2 are
>>
>> n 3 4 5 6 7 8 9 10 11 12 13 14 15
>> d2(n) 6 22 120 714 5040 40296 362880 3628680 39916800 479000880
>> 6227020800 87178286160 1307674368000
>>
>> which have the property that odd and even d2(o) and d2(e) are o! and
>> e! - (e/2)!
>>
>> How does one write a function that will generate sequence a?
>>
>> Eugene McDonnell
>>
>>
>>
>
>
>
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