The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A224846 Smallest k such that (10^n+k, 10^n+k+2) and (10^(n+1)+k, 10^(n+1)+k+2) are two pairs of twin primes with k(n+1) > k(n). 2

%I #16 Jul 24 2013 12:48:39

%S 1,49,91,1117,2929,3001,4831,37237,43897,54409,55669,81931,89809,

%T 194971,271159,556651,628069,639247,1036447,1615597,2075407,2086447,

%U 2414077,3331009,3442789,4088539,4178311,4330681,5834869,6846649,7928047,11222341,15520927,18575911,18615787,22426969,22645189

%N Smallest k such that (10^n+k, 10^n+k+2) and (10^(n+1)+k, 10^(n+1)+k+2) are two pairs of twin primes with k(n+1) > k(n).

%H Pierre CAMI, <a href="/A224846/b224846.txt">Table of n, a(n) for n = 1..75</a>

%e 10^1+1=11 prime as 13 10^2+1=101 prime as 103 so a(1)=1.

%t i = -1; Table[i = i + 2; While[! (PrimeQ[10^n + i] && PrimeQ[10^n + i + 2] && PrimeQ[10^(n + 1) + i] && PrimeQ[10^(n + 1) + i + 2]), i = i + 2]; i, {n, 10}] (* _T. D. Noe_, Jul 23 2013 *)

%o PFGW & SCRIPTIFY

%o SCRIPT

%o DIM n,0

%o DIM k,-1

%o DIMS t

%o OPENFILEOUT myf,a(n).txt

%o LABEL a

%o SET n,n+1

%o LABEL b

%o SET k,k+2

%o SETS t,%d,%d\,;n;k

%o PRP 10^n+k,t

%o IF ISPRP THEN GOTO c

%o GOTO b

%o LABEL c

%o PRP 10^n+k+2,t

%o IF ISPRP THEN GOTO d

%o GOTO b

%o LABEL d

%o PRP 10^(n+1)+k,t

%o IF ISPRP THEN GOTO e

%o GOTO b

%o LABEL e

%o PRP 10^(n+1)+k+2,t

%o IF ISPRP THEN GOTO f

%o GOTO b

%o LABEL f

%o WRITE myf,t

%o SET k,k+2

%o GOTO a

%Y Cf. A124001 (10^n+k and 10^n+k+2 are prime).

%K nonn

%O 1,2

%A _Pierre CAMI_, Jul 22 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 10 13:03 EDT 2023. Contains 363205 sequences. (Running on oeis4.)