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A073627 a(1)=a(2)=1; for n > 2, a(n) is the smallest integer such that a(n) > a(n-1) and a(n)+a(n-1) is prime. 9

%I

%S 1,1,2,3,4,7,10,13,16,21,22,25,28,31,36,37,42,47,50,51,52,55,58,69,70,

%T 79,84,89,90,91,100,111,112,115,118,121,130,133,136,141,142,151,156,

%U 157,160,171,176,177,182,185,188,191,192,197,200,201,208,211,220,223

%N a(1)=a(2)=1; for n > 2, a(n) is the smallest integer such that a(n) > a(n-1) and a(n)+a(n-1) is prime.

%C Essentially the same as A062042. [_John W. Layman_, Oct 11 2013]

%H T. D. Noe, <a href="/A073627/b073627.txt">Table of n, a(n) for n = 1..1000</a>

%t s=1; Join[{1,1}, Table[k=s+1; While[ !PrimeQ[k+s], k++ ]; s=k, {100}]] (* _T. D. Noe_, Nov 02 2009 *)

%o (PARI) FirstTerms(n)={my(x=1,y,a=vector(n),j=2);a[1]=1;a[2]=1;while(j++<=n,y=x+1;while(!isprime(x+y),y++);x=y;a[j]=y);return(a)} \\ _R. J. Cano_, Jan 18 2017

%Y Cf. A073628.

%K nonn

%O 1,3

%A _Amarnath Murthy_, Aug 08 2002

%E Edited by _Matthew Conroy_, Oct 21 2002

%E Definition corrected by _T. D. Noe_, Nov 02 2009

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Last modified December 2 07:33 EST 2021. Contains 349437 sequences. (Running on oeis4.)