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A164937 Near-repdigit primes. 8
101, 113, 131, 151, 181, 191, 199, 211, 223, 227, 229, 233, 277, 311, 313, 331, 337, 353, 373, 383, 433, 443, 449, 499, 557, 577, 599, 661, 677, 727, 733, 757, 773, 787, 797, 811, 877, 881, 883, 887, 911, 919, 929, 977, 991, 997, 1117, 1151, 1171, 1181, 1511 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..22172 (first 5000 terms from Arkadiusz Wesolowski)

Chris Caldwell, The Top 20 Near-repdigit Primes

Chris Caldwell, The Prime Glossary, Near-repdigit prime

Brady Haran and Simon Pampena, Glitch Primes and Cyclops Numbers, Numberphile video (2015)

MATHEMATICA

lst = {}; Do[If[PrimeQ[n] && SortBy[Tally[IntegerDigits[n]], Last][[-1, -1]] == IntegerLength[n] - 1, AppendTo[lst, n]], {n, 101, 10^3}]; lst (* Arkadiusz Wesolowski, Sep 18 2011 *)

lst = {}; Do[r = (10^n - 1)/9; Do[AppendTo[lst, DeleteCases[Select[FromDigits[Permutations[Append[IntegerDigits[a*r], d]]], PrimeQ], r | 2 | 3 | 5 | 7]], {a, 9}, {d, 0, 9}], {n, 2, 6}]; Sort[Flatten[lst]] (* Arkadiusz Wesolowski, Sep 22 2011 *)

PROG

(Python)

from sympy import isprime

from itertools import count, islice

def agen(): # generator of terms

    for d in count(3):

        ds = set()

        for end in "1379":

            ds.update(int(c*(d-1) + end) for c in "123456789" if c != end)

            for diff in "0123456789":

                if end == diff: continue

                cands = (end*i + diff + end*(d-1-i) for i in range(d-1))

                ds.update(int(t) for t in cands if t[0] != "0")

        yield from sorted(t for t in ds if isprime(t))

print(list(islice(agen(), 52))) # Michael S. Branicky, May 17 2022

CROSSREFS

Cf. A105992, A105975, A105976, A105977, A105978, A105979, A105980, A105981, A105982, A065074.

Sequence in context: A248533 A069691 A084414 * A105992 A038370 A084430

Adjacent sequences:  A164934 A164935 A164936 * A164938 A164939 A164940

KEYWORD

nonn,base

AUTHOR

G. L. Honaker, Jr., Aug 31 2009

EXTENSIONS

Three more terms from Lekraj Beedassy, Dec 06 2009

STATUS

approved

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Last modified September 27 19:37 EDT 2022. Contains 357063 sequences. (Running on oeis4.)