

A105992


Nearrepunit primes.


7



101, 113, 131, 151, 181, 191, 211, 311, 811, 911, 1117, 1151, 1171, 1181, 1511, 1811, 2111, 4111, 8111, 10111, 11113, 11117, 11119, 11131, 11161, 11171, 11311, 11411, 16111, 101111, 111119, 111121, 111191, 111211, 111611, 112111, 113111, 131111, 311111, 511111
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OFFSET

1,1


REFERENCES

C. Caldwell and H. Dubner, "The near repunit primes 1(nk1)01(1k)," J. Recreational Math., 27 (1995) 3541.
Heleen, J. P., "More nearrepunit primes 1(nk1)D(1)1(k), D=2,3, ..., 9," J. Recreational Math., 29:3 (1998) 190195.


LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000
Chris Caldwell, The Top 20 Nearrepdigit Primes
Chris Caldwell, The Prime Glossary, Nearrepunit prime


EXAMPLE

a(2)=113 is a term because 113 is a prime and all digits are 1 except one.


MATHEMATICA

lst = {}; Do[r = (10^n  1)/9; Do[AppendTo[lst, DeleteCases[Select[FromDigits[Permutations[Append[IntegerDigits[r], d]]], PrimeQ], r]], {d, 0, 9}], {n, 2, 14}]; Sort[Flatten[lst]] (* Arkadiusz Wesolowski, Sep 20 2011 *)


CROSSREFS

Cf. A000042, A002275, A004022, A046053, A046413, A065074, A034093, A065083, A102782, A118505.
Sequence in context: A069691 A084414 A164937 * A038370 A084430 A182693
Adjacent sequences: A105989 A105990 A105991 * A105993 A105994 A105995


KEYWORD

base,nonn


AUTHOR

Shyam Sunder Gupta, Apr 29 2005


STATUS

approved



