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A099667 a(n) is the largest prime before A002281(n); repdigits repeating 7. 2

%I

%S 5,73,773,7759,77773,777769,7777769,77777761,777777773,7777777741,

%T 77777777767,777777777773,7777777777771,77777777777753,

%U 777777777777773,7777777777777753,77777777777777747,777777777777777743

%N a(n) is the largest prime before A002281(n); repdigits repeating 7.

%H Michael De Vlieger, <a href="/A099667/b099667.txt">Table of n, a(n) for n = 1..1000</a>

%e n=2: 73 is before 77.

%t Table[NextPrime[7 (10^n - 1)/9, -1], {n, 35}]

%t (* Second program: *)

%t Rest[NextPrime[#,-1]&/@LinearRecurrence[{11,-10},{0,7},25]] (* _Harvey P. Dale_, May 24 2015 *)

%Y Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

%K base,nonn

%O 1,1

%A _Labos Elemer_, Nov 17 2004

%E Name changed by _David A. Corneth_, Sep 01 2017

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Last modified March 29 02:19 EDT 2020. Contains 333104 sequences. (Running on oeis4.)