[seqfan] A086421 is duplicate of A000120 ?

Max Alekseyev maxale at gmail.com
Mon Dec 12 17:01:41 CET 2011


SeqFans,

A086421 is defined as "Smallest k>=0 such that 2^(n-k) divides S(m,n)
for all m>0 where S(m,n)=sum(i=0,m, i^n*C(m,i))."

First, it seems that the arguments of S() got swapped (I cannot
reproduce the sequence otherwise). That is, it should be defined as:
Smallest k>=0 such that 2^(n-k) divides S(m,n) for all m>0 where
S(m,n)=sum(i=0,n, i^m*C(n,i)).

Second, A086421(10) must be 2, not 3.

Third, it appears that A086421 is a duplicate A000120 - I did not
prove that yet but it does not look hard.

What should we do about A086421 ?

Regards,
Max



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