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.

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A334217 Irregular table T(n, k) read by rows, n > 0 and k = 1..A334216(n); n-th row corresponds to distinct terms of n-th row of A334215, in ascending order.

Original entry on oeis.org

1, 1, 2, 1, 3, 1, 2, 4, 1, 5, 1, 6, 1, 7, 1, 2, 8, 1, 3, 9, 1, 10, 1, 11, 1, 2, 12, 1, 13, 1, 14, 1, 15, 1, 2, 4, 16, 1, 17, 1, 3, 18, 1, 19, 1, 2, 20, 1, 21, 1, 22, 1, 23, 1, 2, 24, 1, 5, 25, 1, 26, 1, 3, 27, 1, 2, 28, 1, 29, 1, 30, 1, 31, 1, 2, 4, 32, 1, 33
Offset: 1

Views

Author

Rémy Sigrist, Apr 19 2020

Keywords

Examples

			The first rows are:
  n     n-th row
  --    -------------
   1    [1]
   2    [1, 2]
   3    [1, 3]
   4    [1, 2, 4]
   5    [1, 5]
   6    [1, 6]
   7    [1, 7]
   8    [1, 2, 8]
   9    [1, 3, 9]
  10    [1, 10]
  11    [1, 11]
  12    [1, 2, 12]
  13    [1, 13]
  14    [1, 14]
  15    [1, 15]
  16    [1, 2, 4, 16]
		

Crossrefs

Programs

  • PARI
    row(n) = { my (f=factor(n)); Set(apply (k -> prod (i=1, #f~, f[i,1]^(f[i,2]\k)), [1..1+if (n==1, 0, vecmax(f[,2]~))])) }

Formula

T(n, 1) = 1.
T(n, 2) = A261969(n) for any n > 1.
T(n, A334216(n)-1) = A000188(n) for any n > 1.
T(n, A334216(n)) = n.

A334215 T(n, k) is the greatest positive integer m such that m^k divides n; square array T(n, k), n, k > 0 read by antidiagonals downwards.

Original entry on oeis.org

1, 1, 2, 1, 1, 3, 1, 1, 1, 4, 1, 1, 1, 2, 5, 1, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 8, 1, 1, 1, 1, 1, 1, 1, 2, 9, 1, 1, 1, 1, 1, 1, 1, 2, 3, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Rémy Sigrist, Apr 19 2020

Keywords

Examples

			Square array starts:
  n\k|   1  2  3  4  5  6  7  8  9 10
  ---+-------------------------------
    1|   1  1  1  1  1  1  1  1  1  1
    2|   2  1  1  1  1  1  1  1  1  1
    3|   3  1  1  1  1  1  1  1  1  1
    4|   4  2  1  1  1  1  1  1  1  1
    5|   5  1  1  1  1  1  1  1  1  1
    6|   6  1  1  1  1  1  1  1  1  1
    7|   7  1  1  1  1  1  1  1  1  1
    8|   8  2  2  1  1  1  1  1  1  1
    9|   9  3  1  1  1  1  1  1  1  1
   10|  10  1  1  1  1  1  1  1  1  1
   11|  11  1  1  1  1  1  1  1  1  1
   12|  12  2  1  1  1  1  1  1  1  1
   13|  13  1  1  1  1  1  1  1  1  1
   14|  14  1  1  1  1  1  1  1  1  1
   15|  15  1  1  1  1  1  1  1  1  1
   16|  16  4  2  2  1  1  1  1  1  1
		

Crossrefs

Programs

  • PARI
    T(n,k) = { my (f=factor(n)); prod (i=1, #f~, f[i,1]^(f[i,2]\k)) }

Formula

T(n, 1) = n.
T(n, 2) = A000188(n).
T(n, 3) = A053150(n).
T(n, 4) = A053164(n).
T(n, A051903(n)) = A261969(n).
T(n, k) = 1 for any k > A051903(n).
T(n^k, k) = n.
Showing 1-2 of 2 results.