A328446 Table read by rows: the n-th row gives the nonnegative integers k such that n - k is a power of k.

0, 1, 2, 2, 3, 4, 2, 3, 5, 6, 4, 7, 8, 2, 5, 9, 10, 3, 6, 11, 12, 7, 13, 14, 8, 15, 16, 2, 9, 17, 18, 4, 10, 19, 20, 11, 21, 22, 12, 23, 24, 13, 25, 26, 14, 27, 28, 3, 5, 15, 29, 30, 16, 31, 32, 2, 17, 33, 34, 18, 35, 36, 19, 37, 38, 20, 39, 40, 6, 21, 41, 42, 22

Offset: 1

Author

Peter Kagey, Oct 15 2019

Keywords

• nonn
• tabf

Comments

The n-th row has length A309978(n) for n > 1.

Examples

			Table begins
   n | n-th row
  ---+----------
   1 | 0
   2 | 1
   3 | 2
   4 | 2, 3
   5 | 4
   6 | 2, 3, 5
   7 | 6
   8 | 4, 7
   9 | 8
  10 | 2, 5, 9
  11 | 10
  12 | 3, 6, 11
  13 | 12
  14 | 7, 13
  15 | 14
  16 | 8, 15
  17 | 16
  18 | 2, 9, 17
For n = 10 the 10th row is 2, 5, 9 because
10 - 2 = 2^3,
10 - 5 = 5^1, and
10 - 9 = 9^0.
		

Links

• Peter Kagey, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A307092, A309978.

Programs

PARI

row(n) = {if (n==1, return ([0])); my(row = vector(0)); fordiv(n, d, if ((d>1) && (dMichel Marcus, Oct 16 2019