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.

A119802 a(1) = 1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = number of earlier terms of the sequence which equal a(k).

Original entry on oeis.org

1, 1, 2, 2, 2, 2, 4, 4, 2, 2, 6, 6, 6, 6, 2, 2, 2, 2, 10, 10, 10, 10, 2, 2, 12, 12, 4, 4, 4, 4, 12, 12, 2, 2, 14, 14, 14, 14, 6, 6, 14, 14, 6, 7, 7, 7, 14, 14, 14, 14, 4, 4, 4, 4, 14, 14, 4, 4, 12, 12, 12, 12, 8, 8, 2, 2, 16, 16, 16, 16, 12, 12, 16, 16, 7, 7, 7, 7, 16, 16, 16, 16, 4, 4, 4, 4
Offset: 1

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Author

Leroy Quet, May 24 2006

Keywords

Comments

Interpreted as a triangle with row lengths A011782, row m+1 is the frequency of each term in rows 1..m among terms in the sequence thus far (including the part of row m+1 itself thus far). - Neal Gersh Tolunsky, Oct 03 2023

Examples

			8 = 2^2 + 4; so for a(8) we want the number of terms among terms a(1), a(2),... a(7) which equal a(4) = 2. So a(8) = 4.
As a triangle:
      k=1  2   3   4   5   6  7  8 ...
  m=1:  1;
  m=2:  1;
  m=3:  2, 2;
  m=4:  2, 2,  4,  4;
  m=5:  2, 2,  6,  6,  6,  6, 2, 2;
  m=6:  2, 2, 10, 10, 10, 10, 2, 2, 12, 12, 4, 4, 4, 4, 12, 12;
  ...
		

Crossrefs

Cf. A119803, A011782 (row lengths), A365882.

Programs

  • PARI
    A119802(mmax)= { local(a,ncopr); a=[1]; for(m=0,mmax, for(k=1,2^m, ncopr=0; for(i=1,2^m+k-1, if( a[i]==a[k], ncopr++; ); ); a=concat(a,ncopr); ); ); return(a); }
    print(A119802(6)); \\ R. J. Mathar, May 30 2006

Extensions

More terms from R. J. Mathar, May 30 2006