A167118 Each subsequent term in the series describes the digits of the previous term, by tallying their cumulative total within the term. This is similar to the "look and say" sequence, but deviates from it in that blocks of like digits are described individually, according to position.

1, 11, 1121, 11211231, 1121123141221351, 11211231412213511461324271231581, 11211231412213511461324271231581912416

Offset

1,2

Comments

More terms can be represented beyond those listed, but only with symbols to quantify integers greater than ten. Each term contains a replicate of the previous term; the length of each term is twice that of the previous term (The last term in the series does not adhere to this rule because its omitted parts contain nonintegers.).

Links

Table of n, a(n) for n=1..7.

Example

Read aloud the running count of each distinct digit within each term, followed by the digit thus described, to determine each subsequent term, i. e., A(1)=1 produces "first one," or "11," thus A(2)=11; A(2)=11 produces "first one, second one," or "1121," thus A(3)=1121; A(3)=1121 produces "first one, second one, first two, third one," or "11211231," thus A(4)=11211231; A(4)=11211231 produces "first one, second one, first two, third one, fourth one, second two, first three, fifth one," or "1121123141221351," thus A(5)=1121123141221351.

Crossrefs

Cf. A005150.

Sequence in context: A075600 A078568 A015095 * A045981 A090507 A177068

Adjacent sequences: A167115 A167116 A167117 * A167119 A167120 A167121

Keyword

base,easy,nonn

Author

Thomas S. Pedigo, Oct 27 2009

Status

approved