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Look left and tell the least frequent digit string; a(0) = 0, a(n) = concat(c,s), where c > 0 is the number of times the string s, composed of one or more digits, has appeared so far in a(0) to a(n-1) such that a(n) is minimal. Digit strings with leading zeros are ignored.
This is a variation on A329447. Instead of just considering the number of times the digits 0 to 9 have appeared so far in the sequence, we consider all numbers formed by the substrings of each previous entry; from single digits to the entire entry itself. Each value of a(n) is determined by considering the count of all the substrings occurring so far in a(0) to a(n-1) and then choosing the one which forms the lowest number when the count of that substring is concatenated with the substring itself.
Look left and tell the least frequent digit string; a(0) = 0, a(n) = concat(c + ,s, ), where c > 0 is the number of times the string s, composed of one or more digits, has appeared so far such that the number c concatenated with s a(n) is minimal. Digit strings with leading zeros are ignored.
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Look left and tell the least frequent digit string; a(0) = 0, a(n) = a c + b, s, where a c > 0 is the number of times the string b, s, composed of one or more digits, has appeared so far such that the number a c concatenated with b s is minimal. Digit strings with leading zeros are ignored.
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