A340792 List in which n appears ceiling(d(n)/2) = A038548(n) times, where d(n) is the number of divisors of n.

1, 2, 3, 4, 4, 5, 6, 6, 7, 8, 8, 9, 9, 10, 10, 11, 12, 12, 12, 13, 14, 14, 15, 15, 16, 16, 16, 17, 18, 18, 18, 19, 20, 20, 20, 21, 21, 22, 22, 23, 24, 24, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 28, 29, 30, 30, 30, 30, 31, 32, 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 36

Offset

1,2

Comments

The numbers in A075362 arranged in numerical order.

Links

Table of n, a(n) for n=1..73.

Charles Kusniec, Bijection between OEIS sequence A340792 and the positive Triangular Multiplication Table

Formula

T(n,k) = A161906(n,k) * A340791(n,k).

Example

Array begins:
   1
   2
   3
   4  4
   5
   6  6
   7
   8  8
   9  9
  10 10
  11
  12 12 12
  13
  14 14
  15 15
  16 16 16
  17
  18 18 18
  19
  20 20 20
  21 21
  22 22
  23
  24 24 24 24

Prog

(PARI) row(n) = my(d=divisors(n), r1=select(x->(x<=sqrt(n)), d), r2=Vecrev(select(x->(x>=sqrt(n)), d))); vector(#r1, k, r1[k]*r2[k]); \\ Michel Marcus, Jan 22 2021

Crossrefs

Cf. A038548 (row lengths), A075362, A161906, A340791, A061017 (comparable array).

Sequence in context: A099801 A099802 A196266 * A112232 A168389 A039708

Adjacent sequences: A340789 A340790 A340791 * A340793 A340794 A340795

Keyword

nonn,tabf

Author

Charles Kusniec, Jan 21 2021

Status

approved