cp's OEIS Frontend

A319064 A(n, k) is the k-th number b > 1 such that b^(prime(n+i)-1) == 1 (mod prime(n+i)^2) for each i = 0..6, with k running over the positive integers; square array, read by antidiagonals, downwards.

%I A319064 #26 Oct 27 2019 11:25:01
%S A319064 4486949,4651993,20950343,4941649,21184318,23250274,5571593,33538051,
%T A319064 163075007,741652533,11903257,78868324,189850207,882345432,710808570,
%U A319064 19397501,86892632,230695118,1528112512,5126829291,2380570527,19841257,111899224,421883318,1701241810
%N A319064 A(n, k) is the k-th number b > 1 such that b^(prime(n+i)-1) == 1 (mod prime(n+i)^2) for each i = 0..6, with k running over the positive integers; square array, read by antidiagonals, downwards.
%e A319064 The array starts as follows:
%e A319064     4486949,    4651993,    4941649,    5571593,   11903257,   19397501,   19841257
%e A319064    20950343,   21184318,   33538051,   78868324,   86892632,  111899224,  126664001
%e A319064    23250274,  163075007,  189850207,  230695118,  421883318,  422771099,  497941351
%e A319064   741652533,  882345432, 1528112512, 1701241810, 1986592318, 2005090271, 2596285385
%e A319064   710808570, 5126829291
%e A319064   2380570527
%t A319064 rows = 6; t = 6;T = Table[lst = {}; b = 2;
%t A319064    While[Length[lst] < rows - n + 1,
%t A319064      p = Prime[n + Range[0, t]];
%t A319064     If[AllTrue[PowerMod[b, (p - 1), p^2], # == 1 &],
%t A319064      AppendTo[lst, b]]; b++];
%t A319064    lst, {n, rows}];
%t A319064 T // TableForm (* Print the A(n,k) table *)
%t A319064 Flatten[Table[T[[j, i - j + 1]], {i, 1, rows}, {j, 1, i}]] (* _Robert Price_, Oct 03 2019 *)
%o A319064 (PARI) printrow(n, terms) = my(c=0); for(b=2, oo, my(j=0); for(i=0, 6, my(p=prime(n+i)); if(Mod(b, p^2)^(p-1)==1, j++)); if(j==7, print1(b, ", "); c++); if(c==terms, break))
%o A319064 array(rows, cols) = for(x=1, rows, printrow(x, cols); print(""))
%o A319064 array(5, 7) \\ print initial 5 rows and 7 columns of array
%Y A319064 Cf. A244249, A256236.
%Y A319064 Cf. analog for i = 0..t: A319059 (t=1), A319060 (t=2), A319061 (t=3), A319062 (t=4), A319063 (t=5), A319065 (t=7).
%K A319064 nonn,tabl
%O A319064 1,1
%A A319064 _Felix Fröhlich_, Sep 11 2018