[seqfan] Re: b-files needed for some basic sequences

[Olivier Gerard]

I agree and this should be done for most of the triples and couples
sequences of similar kind, since the cardinal of the subset with largest
element equal to n is more fundamental than the original sequence.

Olivier


On Mon, Feb 7, 2011 at 03:32, Robert Israel <israel at math.ubc.ca> wrote:

> A propos A015617: surely there should also be a sequence for the number of
> pairwise coprime triples of positive integers with largest element n,
> thus A015617(n) - A015617(n-1).
> The first 100 elements are
> 0, 0, 1, 1, 5, 1, 11, 6, 12, 5, 31, 6, 45, 14, 21, 24, 79, 15, 101, 27, 49,
> 37, 149, 28, 126, 56, 109, 57, 241, 28, 277, 106, 137, 100, 183, 62, 395,
> 128, 193, 102, 489, 65, 541, 165, 203, 189, 649, 116, 551, 170, 347, 231,
> 829, 147, 506, 234, 434, 307, 1027, 119, 1101, 364, 450, 412, 727, 180,
> 1327, 415, 658, 243, 1493, 261, 1587, 526, 572, 522, 1123, 261, 1855, 435,
> 997, 638, 2059, 268, 1296, 709, 1064, 646, 2367, 272, 1613, 785, 1221, 843,
> 1631, 457, 2805, 722, 1232, 662
>
> Robert Israel                                israel at math.ubc.ca
> Department of Mathematics        http://www.math.ubc.ca/~israel University
> of British Columbia            Vancouver, BC, Canada
>
>
> On Sun, 6 Feb 2011, N. J. A. Sloane wrote:
>
>  Dear SeqFans, The following could all use b-files:
>> A018805, A071778, A015616, A015617.
>>
>> The cross-references will show many other closely related sequences
>> that also are lacking b-files. E.g. A015631, A100448, ...
>>
>> I would like anywhere up to 10000 terms for each, though that
>> may be difficult.
>>
>> These days, of course, you can upload your own b-files by editing the
>> sequence.
>>
>> (Oh, a while back you could not upload a b-file if a b-file
>> already existed. But maybe that has been fixed now? I'm not sure.)
>>
>> At present none of these have b-files.
>>
>> Neil
>>
>>
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>>
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