# [seqfan] Re: A080906?

f.firoozbakht at sci.ui.ac.ir f.firoozbakht at sci.ui.ac.ir
Sun Dec 7 08:05:05 CET 2008

```Dear Zak,

You are right,

1. 23 is missed.
2. Terms after 1373 are wrong.
3. Terms less than 4000 are:

23, 37, 53, 73, 1103, 1117, 1123, 1129, 1153, 1171, 1303, 1307, 1319, 1361,
1367, 1373, 1723, 1741, 1747, 1753, 1759, 1783, 1789, 1907, 1913, 1931, 1973,
1979, 1997, 2311, 2341, 2347, 2371, 2383, 2389, 2903, 2917, 2953, 2971, 3119,
3137, 3167, 3719, 3761, 3767, 3779, 3797

4. I think the definition must change in this way:
Prime numbers with 2k digits such that the first k-digit number and the last
(second) k-digit number are both prime numbers.

Farideh

Quoting zak seidov <zakseidov at yahoo.com>:

> Dear SeqFans,
>
> anyone may wish to edit this:
>
> 1. 23 is missed
> 2. terms after 1373 are wrong
> 4. in %N, it'd be Prime numbers?
>    otherwise why 22 32 52 72 missed?
>
> thx, zak
>
> PS Were i editor i'd returm it to author(?)
>
> %I A080906
> %S A080906
> 37,53,73,1103,1117,1123,1129,1153,1171,1303,1307,1319,1361,1367,1373,
> %T A080906 1523,1531,1543,1553,1559,1567,1571,1579,1583,1597
> %N A080906 Numbers with 2k digits such that the first k digits and
> the last k digits
>                are both prime numbers.
> %F A080906 P. Giannopoulos, The brainteasers (unpublished)
> %Y A080906 Sequence in context: A092105 A101938 A060330
> this_sequence A101940 A036540
>                A141166
> %Y A080906 Adjacent sequences: A080903 A080904 A080905 this_sequence
>  A080907 A080908
>                A080909
> %K A080906 base,easy,nonn
> %O A080906 0,1
> %A A080906 P. Giannopoulos (pgiannop1(AT)yahoo.com), Mar 31 2003
>
>
>
>
>
> _______________________________________________
>
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>

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