cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A319062 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..4, with k running over the positive integers; square array, read by antidiagonals, downwards.

Original entry on oeis.org

19601, 22049, 54568, 48149, 57968, 13543, 52057, 132857, 101399, 296449, 67357, 171793, 132576, 298117, 3414284, 84457, 223568, 296449, 380827, 4029059, 14380864, 85193, 261593, 338168, 1096112, 7040291, 14461231, 3727271, 93493, 282907, 1098599, 1761679
Offset: 1

Views

Author

Felix Fröhlich, Sep 09 2018

Keywords

Examples

			The array starts as follows:
     19601,    22049,    48149,    52057,    67357,    84457,    85193
     54568,    57968,   132857,   171793,   223568,   261593,   282907
     13543,   101399,   132576,   296449,   338168,  1098599,  1244324
    296449,   298117,   380827,  1096112,  1761679,  2498247,  2500716
   3414284,  4029059,  7040291, 10858059, 12249190, 17134811, 19603812
  14380864, 14461231, 18366174, 22811283, 26295533, 33674748, 34998229
   3727271, 27936608, 29998045, 31239565, 34998229, 45331852, 56029298
		

Crossrefs

Cf. analog for i = 0..t: A319059 (t=1), A319060 (t=2), A319061 (t=3), A319063 (t=5), A319064 (t=6), A319065 (t=7).

Programs

  • Mathematica
    rows = 7; t = 4;
    T = Table[lst = {}; b = 2;
       While[Length[lst] < rows,
         p = Prime[n + Range[0, t]];
        If[AllTrue[PowerMod[b, (p - 1), p^2], # == 1 &],
         AppendTo[lst, b]]; b++];
       lst, {n, rows}];
    T // TableForm (* Print the A(n,k) table *)
    Flatten[Table[T[[j, i - j + 1]], {i, 1, rows}, {j, 1, i}]] (* Robert Price, Sep 30 2019 *)
  • PARI
    printrow(n, terms) = my(c=0); for(b=2, oo, my(j=0); for(i=0, 4, my(p=prime(n+i)); if(Mod(b, p^2)^(p-1)==1, j++)); if(j==5, print1(b, ", "); c++); if(c==terms, break))
    array(rows, cols) = for(x=1, rows, printrow(x, cols); print(""))
    array(8, 10) \\ print initial 8 rows and 10 columns of array