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Product of A325907(n) and its 9's complement.
2

%I #35 Sep 21 2019 14:38:07

%S 18,2268,22316868,2222332266866868,22222222333322316666886866866868,

%T 2222222222222222333333332222332266666666888866866666886866866868

%N Product of A325907(n) and its 9's complement.

%F a(n) = A084021(A325907(n)) = A325907(n) * (A002283(2^(n-1)) - A325907(n)).

%F a(n) = A327294(n) - 10^(2^(n-1)) = a(n) = (2 * 10^(2^n) - 3 * 10^(2^(n-1)) - 8)/9 - 2 * A325493(n-1) + A325910(n-1) * 10^(2^(n-1)).

%e a(1) = 3 * 6 = 18.

%e a(2) = 63 * 36 = 2268.

%e a(3) = 3363 * 6636 = 22316868.

%e a(4) = 66663363 * 33336636 = 2222332266866868.

%e -----------------------------------------------

%e a(1) = 18 = 18 - 2 * 0 + 0 * 10^1.

%e a(2) = 2268 = 2188 - 2 * 10 + 1 * 10^2.

%e a(3) = 22316868 = 22218888 - 2 * 1010 + 10 * 10^4.

%e a(4) = 2222332266866868 = 2222222188888888 - 2 * 11011010 + 1101 * 10^8.

%o (Ruby)

%o def A(n)

%o a = [3, 6]

%o b = ([[3]] + (1..n - 1).map{|i| [a[i % 2]] * (2 ** (i - 1))}).reverse.join.to_i

%o b * (10 ** (2 ** (n - 1)) - 1 - b)

%o end

%o def A327266(n)

%o (1..n).map{|i| A(i)}

%o end

%o p A327266(6)

%Y Cf. A002283, A084021, A178630, A325907, A325910, A325493, A327294.

%K nonn

%O 1,1

%A _Seiichi Manyama_, Sep 15 2019