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a(n) = smallest m such that A328330(m) = n, or -1 if n never appears in A328330.
2

%I #44 Jul 31 2023 00:28:54

%S 4,2,1,8,10,22,1088

%N a(n) = smallest m such that A328330(m) = n, or -1 if n never appears in A328330.

%C a(8) = 2008...888 (156 digits).

%H Jens Placke, <a href="/A338255/b338255.txt">Table of n, a(n) for n = 1..8</a>

%H <a href="/index/Ca#calculatordisplay">Index entries for sequences related to calculator display</a>

%e 4 is represented with 4 segments, so a(1) = 4.

%e 2 is represented by 5 segments, 5 is represented by 5 segments so a(2) = 2.

%e 1 is represented by 2 segments, 2 is by 5, 5 by 5 again, so a(3) = 1.

%e [...]

%e 1088 is the solution for 7 steps.

%e 2008..888 (156 digits) is the solution for 8 steps.

%Y Cf. A006942.

%Y Location of first occurrence of n in A328330.

%K base,nonn

%O 1,1

%A _Jens Placke_, Oct 18 2020