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.

A307056 Row n = digits of A025487(n) in primorial base.

Original entry on oeis.org

1, 1, 0, 2, 0, 1, 0, 0, 1, 1, 0, 2, 0, 0, 2, 2, 0, 4, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 3, 0, 0, 2, 0, 0, 0, 2, 0, 2, 0, 2, 2, 0, 0, 3, 1, 0, 0, 4, 0, 0, 0, 4, 1, 1, 0, 4, 4, 0, 0, 6, 0, 0, 0, 6, 2, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 2, 2, 0, 1, 2, 3, 0, 0, 1, 5, 0, 0, 0, 1, 5, 4
Offset: 1

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Author

Michael De Vlieger, Mar 21 2019

Keywords

Comments

A025487 is the sequence of products of primorials (A002110).

Examples

			First rows of this sequence:
   n  A025487(n)  Row n
-------------------------------
   1          1   1
   2          2   1, 0
   3          4   2, 0
   4          6   1, 0, 0
   5          8   1, 1, 0
   6         12   2, 0, 0
   7         16   2, 2, 0
   8         24   4, 0, 0
   9         30   1, 0, 0, 0
  10         32   1, 0, 1, 0
  11         36   1, 1, 0, 0
  12         48   1, 3, 0, 0
  13         60   2, 0, 0, 0
  14         64   2, 0, 2, 0
  15         72   2, 2, 0, 0
  16         96   3, 1, 0, 0
  17        120   4, 0, 0, 0
  18        128   4, 1, 1, 0
  19        144   4, 4, 0, 0
  20        180   6, 0, 0, 0
  21        192   6, 2, 0, 0
  22        210   1, 0, 0, 0, 0
  ...
		

Crossrefs

Programs

  • Mathematica
    f[n_] := {{1}}~Join~Block[{lim = Product[Prime@ i, {i, n}], ww = NestList[Append[#, 1] &, {1}, n - 1], dec}, dec[x_] := Apply[Times, MapIndexed[Prime[First@ #2]^#1 &, x]]; Map[Block[{w = #, k = 1}, Sort@ Prepend[If[Length@ # == 0, #, #[[1]]], Product[Prime@ i, {i, Length@ w}] ] &@ Reap[Do[If[# < lim, Sow[#]; k = 1, If[k >= Length@ w, Break[], k++]] &@ dec Set[w, If[k == 1, MapAt[# + 1 &, w, k], PadLeft[#, Length@ w, First@ #] &@ Drop[MapAt[# + Boole[i > 1] &, w, k], k - 1] ]], {i, Infinity}] ][[-1]] ] &, ww]]; Block[{nn = 10, b}, b = MixedRadix[Reverse@ Prime@ Range@ nn]; Map[IntegerDigits[#, b] &, Union@ Flatten@ f@ nn]]