Concatenate the decimal numbers n n-2 n-4 ...5 3 1 2 4 ... n-5 n-3 n-1 if n is odd, or n n-2 n-4 ... 6 4 2 1 3 5 ... n-5 n-3 n-1 if n is even.

A281254

Concatenate the decimal numbers n n-2 n-4 ...5 3 1 2 4 ... n-5 n-3 n-1 if n is odd, or n n-2 n-4 ... 6 4 2 1 3 5 ... n-5 n-3 n-1 if n is even.

Terms

    a(0) =1a(1) =21a(2) =312a(3) =4213a(4) =53124a(5) =642135a(6) =7531246a(7) =86421357a(8) =975312468a(9) =10864213579

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