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.

A266348 a(1) = 1; for n > 1, a(n) = A004001(n+1) - A072376(n).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 1, 2, 3, 3, 4, 4, 4, 4, 1, 2, 3, 4, 4, 5, 6, 6, 7, 7, 7, 8, 8, 8, 8, 8, 1, 2, 3, 4, 5, 5, 6, 7, 8, 8, 9, 10, 10, 11, 11, 11, 12, 13, 13, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 15, 16, 16, 16, 17, 18, 19, 19, 20, 21, 21
Offset: 1

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Author

Antti Karttunen, Jan 22 2016

Keywords

Comments

When the terms are arranged as successively larger batches of 2^n, the terms A(n,k), k = 1 .. 2^n, on row n give the cumulative number of 1's encountered since the beginning of the row n of similarly organized irregular table A265754, up to and including the k-th term on that row:
1;
1, 1;
1, 2, 2, 2;
1, 2, 3, 3, 4, 4, 4, 4;
1, 2, 3, 4, 4, 5, 6, 6, 7, 7, 7, 8, 8, 8, 8, 8;
...

Crossrefs

Programs

  • Mathematica
    lim = 100; b[1] = 1; b[2] = 1; b[n_] := b[n] = b[b[n - 1]] + b[n - b[n - 1]]; s = CoefficientList[Series[1/(2 - 2 x) (2 x - x^2 + Sum[ 2^(k - 1) x^2^k, {k, Floor@ Log2@ lim}]), {x, 0, lim}], x]; {1}~Join~Table[b[n + 1] - s[[n + 1]], {n, 2, lim}] (* Michael De Vlieger, Jan 26 2016, after Robert G. Wilson v at A004001 *)
  • Scheme
    (define (A266348 n) (if (= 1 n) 1 (- (A004001 (+ 1 n)) (A072376 n))))

Formula

a(1) = 1; for n > 1, a(n) = A004001(n+1) - A072376(n) = A004001(n+1) - 2^(A000523(n)-1).