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Smallest prime of the form prime(k) concatenated with prime(k+n).
4

%I #6 Nov 18 2018 00:46:36

%S 23,37,311,211,317,523,3767,223,229,337,1153,241,347,353,359,1783,367,

%T 47137,271,379,383,283,397,53173,5107,17137,3109,41179,2113,11149,

%U 2131,2137,29191,19181,11173,3163,3167,5179,19211,2179,3191,5197,7211,13229

%N Smallest prime of the form prime(k) concatenated with prime(k+n).

%e a(4) = 211 = prime(1) followed by prime(1+4).

%t c[r_, s_] := ToExpression[ToString[r] <> ToString[s]]; Do[k = 1; While[ !PrimeQ[c[Prime[k], Prime[n + k]]], k++ ]; Print[c[Prime[k], Prime[n + k]]], {n, 1, 100}] (* _Ryan Propper_, Sep 02 2005 *)

%Y Cf. A089783.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Nov 24 2003

%E Corrected and extended by _Ryan Propper_, Sep 02 2005