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Concatenation of prime numbers in increasing order up to the n-th and then in decreasing order.
4

%I #9 Oct 02 2022 18:12:45

%S 2,232,23532,2357532,2357117532,23571113117532,235711131713117532,

%T 2357111317191713117532,23571113171923191713117532,

%U 235711131719232923191713117532,2357111317192329312923191713117532

%N Concatenation of prime numbers in increasing order up to the n-th and then in decreasing order.

%H Harvey P. Dale, <a href="/A066622/b066622.txt">Table of n, a(n) for n = 1..174</a>

%t Table[FromDigits[Flatten[IntegerDigits/@Join[Prime[Range[n]],Reverse[Most[Prime[Range[n]]]]]]],{n,12}] (* _Harvey P. Dale_, Oct 02 2022 *)

%K easy,nonn,base

%O 1,1

%A _Amarnath Murthy_, Dec 25 2001

%E More terms from _Sascha Kurz_, Mar 23 2002