[seqfan] Re: like A004080 but for 1/(2i) and more
davidrabahy at comcast.net
davidrabahy at comcast.net
Wed Jun 24 19:25:36 CEST 2020
Of course you are correct; I’m not sure how I got myself confused. A014537 is the sequence I was looking for.
Is the diagonalization 1,3,4550,… interesting enough for an OEIS entry?
From: M. F. Hasler <seqfan at hasler.fr>
Sent: Tuesday, June 23, 2020 11:48 PM
To: DavidRabahy at comcast.net
Cc: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
Subject: Re: [seqfan] like A004080 but for 1/(2i) and more
On Tue, Jun 23, 2020 at 10:33 PM David Rabahy <DavidRabahy at comcast.net <mailto:DavidRabahy at comcast.net> > wrote:
Least k such that H2(k) >= n, where H2(k) is the even harmonic number sum_{i=1..k} 1/(2i);
n
1 - 5
2 - 31
3 - 227
4 - 1674
Unless I'm wrong it should be 4, not 5, for n=1 above,
and more generally, A4080(2n), for obvious reasons :
Clearly this idea could be generalized, i.e. where Hq(k) is the qth harmonic number sum_{i=1..k} 1/(qi).
which is the same as H(k)/q, whence your sequence should be A4080(qn).
- Maximilian
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