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A349951 Similar to the "Look and Say" sequence, with the added requirement that every third digit describes the location of a digit in blocks of three in the previous term. 0
1, 111, 311, 131211, 111131111122212, 311112132112313114224125115125, 131211212122113133123214124135115135216146227147118128158219159111012101510 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The sequence has a different pattern if, instead of including integers greater than ten in the description of each block of three, one uses symbols to represent those numbers. For example, in a(7), if the subsequence "111012101510" is replaced by "11A12A15A" then the interaction of digits with each other is altered.
LINKS
EXAMPLE
a(1) is read as "one one in the first block", so a(2) is 111.
a(2) is read as "three ones in the first block", so a(3) is 311.
a(3) is read as "one three in the first block, two ones in the first block", so a(4) is 131211.
a(4) is read as "one one in the first block, one three in the first block, one one in the first block, one two in the second block, two ones in the second block", so a(5) is 111131111122212.
MATHEMATICA
{1}~Join~NestList[(s=Split/@Partition[IntegerDigits[#], 3]; FromDigits@Flatten@Table[Join[Reverse@#, IntegerDigits[k]]&/@({First@#, Length@#}&/@#&/@s)[[k]], {k, Length@s}])&, 111, 5] (* Giorgos Kalogeropoulos, Dec 08 2021 *)
CROSSREFS
Cf. A005150.
Sequence in context: A097650 A271312 A171773 * A244857 A225329 A277960
KEYWORD
nonn,base
AUTHOR
Thomas S. Pedigo, Dec 06 2021
STATUS
approved

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Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)