A344828 - OEIS

A344828

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.

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

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OFFSET

1,1

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..100

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).

Sequence in context: A289564 A319061 A339533 * A260066 A105979 A183779

Adjacent sequences: A344825 A344826 A344827 * A344829 A344830 A344831

KEYWORD

nonn

AUTHOR

Felix Fröhlich, May 29 2021

EXTENSIONS

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

STATUS

approved