cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A154475 Number of opening (equally: closing) brackets in each term of Wolfram's Symbolic Rewriting system A154473-A154474.

Original entry on oeis.org

5, 7, 7, 8, 8, 14, 19, 24, 28, 31, 36, 42, 45, 47, 49, 50, 50, 50, 51, 51, 51, 54, 55, 55, 55, 56, 56, 56, 58, 60, 61, 61, 61, 62, 62, 62, 65, 66, 66, 66, 67, 67, 67, 70, 72, 74, 75, 75, 75, 76, 76, 76, 79, 80, 80, 80, 81, 81, 81, 83, 85, 86, 86, 86, 87, 87, 87, 92, 93, 93
Offset: 0

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Author

Antti Karttunen, Jan 11 2009

Keywords

Comments

2*a(n) gives the number of bits in A154474(n).

Examples

			The iteration starts from the initial term e[e[e][e]][e][e], which contains 5 ['s (and also 5 ]'s), thus a(0)=5.

Links

Crossrefs

a(n) = A029837(1+A154473(n))/2. a(n) = A154476(n)-1.

Formula

a(n) = A072643(A154472(n)).

A154474 a(n) = A007088(A154473(n)).

Original entry on oeis.org

1101001010, 10101101010010, 11001110010010, 1011011100100010, 1110111001000010, 1101110010001110111001000100, 10111001001101110010011101110010001000
Offset: 0

Views

Author

Antti Karttunen, Jan 11 2009

Keywords

Comments

This sequence gives the parenthesis expressions shown at the upper right corner image of the page 103 of NKS, with left brackets (black squares) converted to 1's and right brackets (white squares) converted to 0's. Compare to A080070, A122242, A122245.

Links

A154472 a(n) = A126309(A154471(n)).

Original entry on oeis.org

42, 218, 359, 875, 1763, 2359496, 926357642, 1431707647759, 239418125921492, 9138627621456887, 5265474933763866437, 36640566669911088560059, 1544449741807406472977531, 12634727265105076809694418
Offset: 0

Views

Author

Antti Karttunen, Jan 11 2009

Keywords

Comments

This sequence essentially gives the iterated S-expressions of the sequence A154471, with ()'s removed. See A154473.

Links

Crossrefs

a(n) = A080300(A154473(n)).
Showing 1-3 of 3 results.

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