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 A213884 For the smallest k >= 1, the smallest single-digit j such that (10^k-j)*10^n-1 is prime. 3
 1, 4, 1, 2, 2, 5, 1, 2, 1, 2, 1, 4, 4, 5, 5, 1, 4, 7, 1, 4, 2, 4, 4, 1, 2, 8, 7, 4, 1, 1, 2, 1, 1, 4, 7, 4, 1, 1, 7, 4, 8, 2, 7, 4, 8, 8, 7, 2, 2, 1, 8, 2, 8, 5, 7, 1, 8, 4, 8, 1, 4, 1, 4, 7, 1, 2, 8, 2, 4, 1, 4, 8, 4, 5, 8, 2, 1, 2, 7, 7, 5, 1, 4, 8, 7, 4, 1, 4, 2, 2, 4, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS These j are the associated shifts to be paired with the k-values of A213883. There are no multiples of 3 here, as explained in A213883. For the first 2200 values of n, there is always at least one pair (k,j) that delivers a prime with the conditions. LINKS Pierre CAMI, Table of n, a(n) for n = 1..2200 EXAMPLE j=1 associated with the prime 89, j=4 associated with 599, j=1 associated with 8999, j=2 with 79999 are the first 4 entries. MAPLE A213884 := proc(n)     for k from 1 do         for j from 0 to 9 do             if isprime( (10^k-j)*10^n-1) then                 return j;             end if;         end do:     end do:     return 0 ; end proc: # R. J. Mathar, Jul 20 2012 PROG SCRIPT DIM nn, 0 DIM jj DIM kk DIMS tt OPENFILEOUT myfile, a(n).txt LABEL loopn SET nn, nn+1 IF nn>2200 THEN END SET kk, 0 LABEL loopk SET kk, kk+1 IF kk>2*nn THEN GOTO loopn SET jj, 0 LABEL loopj SET jj, jj+1 IF jj%3==0 THEN SET jj, jj+1 IF jj>9 THEN GOTO loopk SETS tt, %d, %d, %d\,; nn; kk; jj PRP (10^kk-jj)*10^nn-1, tt IF ISPRP THEN GOTO a IF ISPRIME THEN GOTO a GOTO loopj LABEL a WRITE myfile, tt GOTO loopn CROSSREFS Cf. A213883. Sequence in context: A106437 A279605 A054713 * A117021 A222213 A010473 Adjacent sequences:  A213881 A213882 A213883 * A213885 A213886 A213887 KEYWORD nonn AUTHOR Pierre CAMI, Jun 29 2012 STATUS approved

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Last modified July 4 12:08 EDT 2022. Contains 355075 sequences. (Running on oeis4.)