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A089712 Smallest prime as a concatenation k and k-n. 2

%I

%S 11,43,31,41,73,61,71,103,113,101,199,3019,131,163,151,227,193,181,

%T 191,223,211,3413,3917,241,251,283,271,281,313,367,311,409,331,5623,

%U 373,383,5519,5417,457,401,433,421,431,463,6521,461,5711,503,491,523,577,521

%N Smallest prime as a concatenation k and k-n.

%C a(17) = 181, obtained as a concatenation of 18 followed by 18 - 17 = 1.

%p ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1),j=1..nops(s))): end: a:=proc(n) local k,m: for k from n+1 do m:=ds([op(convert(k-n,base,10)),op(convert(k,base,10))]): if isprime(m) then RETURN(m) fi od: end: seq(a(n),n=0..60); # C. Ronaldo

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Nov 17 2003

%E Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004

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Last modified August 14 13:51 EDT 2020. Contains 336481 sequences. (Running on oeis4.)