[seqfan] Re: Ali Sada's A364054
Ali Sada
pemd70 at yahoo.com
Mon Oct 23 05:47:46 CEST 2023
Thank you, Neil. I really appreciate it.
If we change the definition to "a(1) = 3; for n > 1, a(n) is the least "odd prime" not already in the sequence such that a(n) == a(n-1) (mod prime(n-1))."
This sequence might stop at one point when a(n) mod prime(n) = prime(n+1), given that prime(n+1) has not already appeared in the sequence. I would really appreciate it if someone could calculate more terms in this sequence. Maybe we will get lucky with a relatively small prime.
3, 5, 11, 31, 17, 61, 113, 79, 41, 179, 353, 43, 191, 109, 23,211, 317, 199, 443, 577, 151, 881, 1039, 541, 7, 977, 1381, 557, 1627, 101, 1231,1993, 421, 2339, 1783, 293, 3011, 499, 173, 3847, 733, 1091, 367, 2659, 2273, 1879,1481, 3169, 47, 1409, 1867, 2333, 3767, 2803, 1297, 269, 1321, 4549, 2381, 719,157, 1289, 4219, 2377, 2999, 1747, 479, 4451, 6473, 227, 3019, 1607, 3761, 1559,67, 1583, 3881, 769, 2357, 6367, 641, 4831, 3989, 9161, 1367, 4001, 457, 4049, 1307,4073, 2221, 5023, 233, 4129, 11003, 8009, 967, 4021, 10273, 859, 3023
Best,
Ali
On Sunday, October 22, 2023 at 05:46:53 PM GMT+1, Neil Sloane <njasloane at gmail.com> wrote:
The definition involves the primes, but otherwise this is quite similar to
Recaman's A005132. However, the graph seems a bit simpler than Recaman's,
since it appears to be dominated by pairs of straight lines, one descending
and one ascending (as can be seen from Chai Wah Wu's b-file). 5 is still
missing even after 10K terms. It would be nice to know more. (I added some
comments to the entry.)
Best regards
Neil
Neil J. A. Sloane, Chairman, OEIS Foundation.
Also Visiting Scientist, Math. Dept., Rutgers University,
Email: njasloane at gmail.com
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