A349257 Largest integer that can be expressed as Sum_{k=1..n} k/p(k), where p is a permutation of [n].

0, 1, 2, 3, 6, 7, 10, 11, 15, 18, 21, 22, 27, 28, 32, 36, 40, 41, 46, 47

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

a(n) = 1 + a(n-1) if n is prime. - Alois P. Heinz, Nov 12 2021

Prog

(Ruby)
def A(n)
  max = 0
  (1..n).to_a.permutation{|i|
    m = (1..n).inject(0){|s, j| s + j / i[j - 1].to_r}
    if m.denominator == 1
      max = m if max < m
    end
  }
  max.to_i
end
def A349257(n)
  (0..n).map{|i| A(i)}
end
p A349257(8)

Crossrefs

Cf. A022819, A073090, A349277.

Sequence in context: A117206 A026443 A345251 * A204323 A278965 A032858

Adjacent sequences: A349254 A349255 A349256 * A349258 A349259 A349260

Keyword

nonn,more

Author

Seiichi Manyama, Nov 12 2021

Extensions

a(12)-a(19) from Alois P. Heinz, Nov 12 2021

Status

approved