The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A344828

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a(n) is the smallest b > 1 such that prime(n), prime(n+1), prime(n+2) and prime(n+3) are all base-b Wieferich primes.
(history; published version)

#10 by OEIS Server at Tue Oct 10 12:14:43 EDT 2023

LINKS

Max Alekseyev, <a href="/A344828/b344828_1.txt">Table of n, a(n) for n = 1..100</a>

#9 by Michel Marcus at Tue Oct 10 12:14:43 EDT 2023

STATUS

reviewed

approved

Discussion

Tue Oct 10

12:14

OEIS Server: Installed first b-file as b344828.txt.

#8 by Joerg Arndt at Tue Oct 10 11:25:23 EDT 2023

STATUS

proposed

reviewed

#7 by Max Alekseyev at Tue Oct 10 11:16:55 EDT 2023

STATUS

editing

proposed

#6 by Max Alekseyev at Tue Oct 10 11:16:49 EDT 2023

LINKS

Max Alekseyev, <a href="/A344828/b344828_1.txt">Table of n, a(n) for n = 1..100</a>

#5 by Max Alekseyev at Tue Oct 10 11:14:00 EDT 2023

DATA

557, 1207, 1451, 13543, 24675, 39016, 217682, 165407, 1357748, 399254, 1146590, 325346, 1895206, 3365181, 4674177, 21251205, 40698745, 6795147, 36463448, 12717474, 54383927, 7411274, 35989426, 101112784, 86045167, 13128506, 276293632, 169093089, 223680564, 137073637

KEYWORD

nonn,more

nonn

EXTENSIONS

Terms a(24) onward from Max Alekseyev, Oct 10 2023

STATUS

approved

editing

#4 by N. J. A. Sloane at Mon May 31 21:31:34 EDT 2021

STATUS

proposed

approved

#3 by Felix Fröhlich at Sat May 29 07:35:01 EDT 2021

STATUS

editing

proposed

#2 by Felix Fröhlich at Sat May 29 07:29:11 EDT 2021

NAME

allocated for Felix Fröhlich

a(n) is the smallest b > 1 such that prime(n), prime(n+1), prime(n+2) and prime(n+3) are all base-b Wieferich primes.

DATA

557, 1207, 1451, 13543, 24675, 39016, 217682, 165407, 1357748, 399254, 1146590, 325346, 1895206, 3365181, 4674177, 21251205, 40698745, 6795147, 36463448, 12717474, 54383927, 7411274, 35989426

OFFSET

1,1

PROG

(PARI) a(n) = my(v=[prime(n)]); while(#v < 4, v=concat(v, nextprime(v[#v]+1))); for(b=2, oo, for(k=1, #v, if(Mod(b, v[k]^2)^(v[k]-1)!=1, break, if(k==#v, return(b)))))

CROSSREFS

Cf. A039678, A259075. Column 4 of A286816.

Cf. smallest b > 1 such that prime(n+i) is a base-b Wieferich prime for each i = 0..k: A039678 (k=0), A259075 (k=1), A344827 (k=2), A344829 (k=4), A344830 (k=5), A344831 (k=6), A344832 (k=7).

KEYWORD

allocated

nonn,more

AUTHOR

Felix Fröhlich, May 29 2021

STATUS

approved

editing

#1 by Felix Fröhlich at Sat May 29 07:07:46 EDT 2021

NAME

allocated for Felix Fröhlich

KEYWORD

allocated

STATUS

approved