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%I #36 Sep 21 2019 14:39:34
%S 28,2368,22326868,2222332366866868,22222222333322326666886866866868,
%T 2222222222222222333333332222332366666666888866866666886866866868
%N a(n) = (A325907(n) + 1) * (10^(2^(n-1)) - A325907(n)).
%C a(n) is composed of digits {2,3,6,8}.
%F a(n) = 2 * (10^(2^n) + 3 * 10^(2^(n-1)) - 4)/9 - 2 * A325493(n-1) + A325910(n-1) * 10^(2^(n-1)).
%e a(1) = 2 * 10^1 + 8.
%e a(2) = 23 * 10^2 + 68.
%e a(3) = 2232 * 10^4 + 6868.
%e a(4) = 22223323 * 10^8 + 66866868.
%e a(5) = 2222222233332232 * 10^16 + 6666886866866868.
%e And
%e 2 = 2 * (10^1 - 1)/9 + 0.
%e 23 = 2 * (10^2 - 1)/9 + 1.
%e 2232 = 2 * (10^4 - 1)/9 + 10.
%e 22223323 = 2 * (10^8 - 1)/9 + 1101.
%e 2222222233332232 = 2 * (10^16 - 1)/9 + 11110010.
%e And
%e 8 = 8 * (10^1 - 1)/9 - 2 * 0.
%e 68 = 8 * (10^2 - 1)/9 - 2 * 10.
%e 6868 = 8 * (10^4 - 1)/9 - 2 * 1010.
%e 66866868 = 8 * (10^8 - 1)/9 - 2 * 11011010.
%e 6666886866866868 = 8 * (10^16 - 1)/9 - 2 * 1111001011011010.
%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 + 1) * (10 ** (2 ** (n - 1)) - b)
%o end
%o def A327294(n)
%o (1..n).map{|i| A(i)}
%o end
%o p A327294(6)
%Y Cf. A325907, A325910, A325493, A327266.
%K nonn
%O 1,1
%A _Seiichi Manyama_, Sep 16 2019
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