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A283720 Main diagonal of A283675. 2

%I #15 Oct 24 2018 02:32:46

%S 1,-1,-16,-19619,-4294403215,-298022109672568357,

%T -10314423865939993706950978963,

%U -256923577039780637227768848162543179896514,-6277101735175091675863380669683250419973895230549186236030

%N Main diagonal of A283675.

%H Seiichi Manyama, <a href="/A283720/b283720.txt">Table of n, a(n) for n = 0..26</a>

%t Table[SeriesCoefficient[Product[(1 - x^k)^(k^(n*k)), {k, 1, 10}], {x, 0, n}], {n, 0, 10}] (* _Indranil Ghosh_, Mar 17 2017 *)

%o (Ruby)

%o def s(k, i)

%o s = 0

%o (1..i).each{|j| s += j ** (k * j + 1) if i % j == 0}

%o s

%o end

%o def A(k, n)

%o ary = [1]

%o s_ary = [0] + (1..n).map{|i| s(k, i)}

%o (1..n).each{|i| ary << (1..i).inject(0){|s, j| s - ary[-j] * s_ary[j]} / i}

%o ary

%o end

%o def A283720(n)

%o (0..n).map{|i| A(i, i)[-1]}

%o end

%Y Cf. A283675.

%K sign

%O 0,3

%A _Seiichi Manyama_, Mar 15 2017

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Last modified April 24 06:52 EDT 2024. Contains 371920 sequences. (Running on oeis4.)