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.

A294306 Irregular triangle read by rows: T(n, m) = total number of times the different values appear in row n of A280269, where 0 <= m <= A280274(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 3, 1, 2, 1, 3, 1, 1, 1, 1, 1, 5, 2, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 4, 1, 1, 1, 5, 2, 1, 1, 1, 1, 1, 5, 2, 1, 3, 1, 1, 3, 1, 1, 1, 1, 1, 1, 7, 3, 1, 2, 1, 3, 1, 1, 1, 1, 3, 1, 5, 2, 1, 1, 1, 7, 6, 3, 1, 1, 1, 1, 5
Offset: 1

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Author

Michael De Vlieger, Oct 30 2017

Keywords

Comments

The numbers i in A162306(n) divide n^k with k >= 0; these k are listed in row n of A280269.
Row 1 = 1 and T(n, 0) = 1 for all n, since 1 is the empty product and divides n^0.
Row p = 1, 1, (row length = 2) since the only divisors of p are 1 and p; 1 | p^0, and p | p^1.
Row p^e = 1, e, since the only numbers in A162306(p^e) are 1 and p^k for 1 <= k <= e.
Row length of a(n) > 2 for n with omega(n) > 1.
Total of row n = A010846(n).
Sum of terms of T(n, m) with m <= 1 in row n = A000005(n).
Sum of terms of T(n, m) with m > 1 = A243822(n).
Terms in row n of A294306 start at 1, generally quickly rise to a maximum, then gradually decline at m = A280274(n).

Examples

			Row n of A280269(10) = 0, 1, 2, 1, 3, 1, corresponding to A162306(10) = 1, 2, 4, 5, 8, 10, since 1 | 10^0, 2 | 10^1, 4 | 10^2, 5 | 10^1, 8 | 10^3, and 10 | 10^1. There is 1 zero, 3 ones, 1 two, and 1 three, thus a(10) = 1, 3, 1, 1. sum(a(10)) = A010846(10) = 6. Length of a(10) = A280274(10) + 1 = 4.
Triangle begins:
   1:  1
   2:  1  1
   3:  1  1
   4:  1  2
   5:  1  1
   6:  1  3  1
   7:  1  1
   8:  1  3
   9:  1  2
  10:  1  3  1  1
  11:  1  1
  12:  1  5  2
  13:  1  1
  14:  1  3  1  1
  15:  1  3  1
  16:  1  4
  17:  1  1
  18:  1  5  2  1  1
  19:  1  1
  20:  1  5  2
  ...
		

Crossrefs

Programs

  • Mathematica
    Table[Tally[#][[All, -1]] &@ Map[SelectFirst[Range[0, Floor@ Log2@ n], Function[k, Divisible[n^k, #]]] &, Select[Range@ n, PowerMod[n, Floor@ Log2@ n, #] == 0 &]], {n, 32}] // Flatten (* Michael De Vlieger, Oct 30 2017 *)