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.

A352740 Irregular table T(n, k) read by rows; the n-th row contains, in ascending order, the numbers k < n such that for any base b >= 2, the sum of digits of n and k in base b are different.

Original entry on oeis.org

0, 0, 0, 2, 0, 3, 0, 4, 0, 0, 4, 6, 0, 6, 7, 0, 7, 8, 0, 8, 0, 6, 8, 9, 10, 0, 11, 0, 12, 0, 10, 12, 0, 8, 12, 14, 0, 13, 15, 0, 14, 15, 16, 0, 15, 16, 0, 16, 17, 18, 0, 19, 0, 20, 0, 0, 12, 16, 18, 20, 21, 22, 0, 23, 0, 24, 0, 18, 24, 0, 14, 21, 24, 25, 26
Offset: 1

Views

Author

Rémy Sigrist, Mar 31 2022

Keywords

Comments

A352671 gives row lengths.

Examples

			irregular table begins:
     1:    [0]
     2:    [0]
     3:    [0, 2]
     4:    [0, 3]
     5:    [0, 4]
     6:    [0]
     7:    [0, 4, 6]
     8:    [0, 6, 7]
     9:    [0, 7, 8]
    10:    [0, 8]
		

Crossrefs

Cf. A216789, A352671 (row lengths).

Programs

  • PARI
    row(n) = { my (v=[]); for (k=0, n-1, my (ok=1); for (b=2, max(2, n+1), if (sumdigits(n, b)==sumdigits(k, b), ok=0; break)); if (ok, v=concat(v,k))); v }

Formula

T(n, 1) = 0.