The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A366835

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A366835

In the pair (A246655(n), A246655(n+1)), how many primes are there?
(history; published version)

#40 by OEIS Server at Wed Nov 08 11:21:46 EST 2023

LINKS

Michael De Vlieger, <a href="/A366835/b366835_1.txt">Table of n, a(n) for n = 1..10000</a>

#39 by N. J. A. Sloane at Wed Nov 08 11:21:46 EST 2023

STATUS

editing

approved

Discussion

Wed Nov 08

11:21

OEIS Server: Installed first b-file as b366835.txt.

#38 by N. J. A. Sloane at Wed Nov 08 11:21:10 EST 2023

NAME

a(n) is the number of primes in In the pair (A246655(n), A246655(n+1))., how many primes are there?

STATUS

proposed

editing

Discussion

Wed Nov 08

11:21

N. J. A. Sloane: Improved the definition.

#37 by Jon E. Schoenfield at Mon Oct 30 23:45:31 EDT 2023

STATUS

editing

proposed

Discussion

Tue Oct 31

03:51

Paolo Xausa: Thank you Jon.

#36 by Jon E. Schoenfield at Mon Oct 30 23:44:13 EDT 2023

EXAMPLE

a(14) = 0 because in the 14-th 14th prime power pair (25 and 27) there are no primes.

STATUS

proposed

editing

Discussion

Mon Oct 30

23:45

Jon E. Schoenfield: Per the Style Sheet at  https://oeis.org/wiki/Style_Sheet#Spelling_and_notation

#35 by Andrew Howroyd at Sun Oct 29 15:55:44 EDT 2023

STATUS

editing

proposed

Discussion

Mon Oct 30

11:01

Michel Marcus: thank you Andrew

#34 by Andrew Howroyd at Sun Oct 29 15:54:09 EDT 2023

NAME

a(n) is the number of primes in the pair (A246655(n), A246655(n+1)) pair.

PROG

(PARI) lista(nn) = my(v=[p| p <- [1..nn], isprimepower(p)]); vector(#v-1, k, primepiisprime(v[k+1]) - primepi+ isprime(v[k]-+1])); \\ Michel Marcus, Oct 26 2023

STATUS

reviewed

editing

Discussion

Sun Oct 29

15:55

Andrew Howroyd: Oh I see. Let me just fix Michel's program which is leading me astray.

#33 by Michael De Vlieger at Sun Oct 29 15:20:51 EDT 2023

STATUS

proposed

reviewed

Discussion

Sun Oct 29

15:37

Andrew Howroyd: The Name is not good here. I don't think "in the (A246655(n), A246655(n+1)) pair" suggests what you mean.

15:38

Andrew Howroyd: rather: between A246655(n) and A246655(n+1) inclusive. ?

15:45

Andrew Howroyd: or if preferred: in the interval [A246655(n), A246655(n+1)] ?

15:48

Paolo Xausa: Andrew: that was similar to my original name. But there can't be any primes between A246655(n) and A246655(n+1) (exclusive), by definition of A246655; so I thought the new name was simpler and made comments simpler, too.

#32 by Paolo Xausa at Sun Oct 29 15:00:20 EDT 2023

STATUS

editing

proposed

#31 by Paolo Xausa at Sun Oct 29 12:30:08 EDT 2023

COMMENTS

First 0 terms appear at n = 6, 14, 41, 359, 3589, corresponding to consecutive prime powers (8,9), (25,27), (121,125), (2187,2197) and (32761,32768), respectively (cf. A068315 and A068435).