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A125197 Numbers such that pre- and post-concatenating 7, 13 and 31 results in six primes. 0
19, 3583, 11287, 62989, 63409, 89491, 93187, 104107, 106783, 155851, 178351, 1082467, 1219399, 1510207, 1566613, 1581469, 2246173, 2920693, 3081499, 3342277, 3523339, 3781849, 3820543, 4010161, 4824163, 4865827, 6091597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is conjectured that 7, 13 and 31 is the only triple with this property

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

3583 is a member as 3583, 73583, 35837, 123583, 358313, 313583, 358331 are all prime.

CROSSREFS

Sequence in context: A287938 A225602 A195756 * A238563 A281820 A213450

Adjacent sequences:  A125194 A125195 A125196 * A125198 A125199 A125200

KEYWORD

hard,nonn,base

AUTHOR

Anton Vrba (antonvrba(AT)yahoo.com), Jan 13 2007

STATUS

approved

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Last modified July 23 22:47 EDT 2019. Contains 325278 sequences. (Running on oeis4.)