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.

A322762 Irregular triangle read by rows: to get row n, take partitions of n ordered as in A080577, and in each partition, change each j-th occurrence of k to j; use compressed notation as in A322761.

Original entry on oeis.org

1, 1, 12, 1, 11, 123, 1, 11, 12, 112, 1234, 1, 11, 11, 112, 121, 1123, 12345, 1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456, 1, 11, 11, 112, 11, 111, 1123, 121, 112, 1112, 11234, 1231, 12123, 112345, 1234567, 1, 11, 11, 112, 11, 111, 1123, 12, 111
Offset: 1

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Author

N. J. A. Sloane, Dec 30 2018

Keywords

Examples

			Triangle begins:
  1,
  1, 12,
  1, 11, 123,
  1, 11, 12, 112, 1234,
  1, 11, 11, 112, 121, 1123, 12345,
  1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456,
  ...
For example, the 11 partitions of 6 are:
6, 51, 42, 411, 33, 321, 3111, 222, 2211, 21111, 111111,
and applying the transformation we get:
1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456.
		

References

  • D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.2.1.5, Problem 73, pp. 415, 761.

Crossrefs

Programs

  • Maple
    b:= (n, i)-> `if`(n=0 or i=1, [cat($1..n)], [(t->
        seq(map(x-> cat($1..(t+1-j), x), b(n-i*(t+1-j)
        , i-1))[], j=1..t))(iquo(n, i)), b(n, i-1)[]]):
    T:= n-> map(parse, b(n$2))[]:
    seq(T(n), n=1..10);  # Alois P. Heinz, Dec 30 2018

Extensions

More terms from Alois P. Heinz, Dec 30 2018