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.

A298425 Lexicographically earliest sequence of distinct positive terms such that, for any n> 0, Sum_{k = 1..n} 10^(n-k) * a(k) can be computed without carry in decimal base.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 100, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1000, 20, 21, 22, 23, 24, 25, 26, 27, 28, 1001, 29, 101, 30, 31, 32, 33, 34, 35, 36, 37, 1002, 38, 102, 39, 103, 40, 41, 42, 43, 44, 45, 46, 1003, 47, 104, 48, 105, 49, 1004, 50, 51, 52
Offset: 1

Views

Author

Rémy Sigrist, Jan 19 2018

Keywords

Comments

More informally: write the terms in decimal under each other, right-justified; the digits on each diagonal in upwards direction sum at most to 9.
See also A298359 for a similar sequence.

Examples

			The first 25 terms, alongside 10^(25-n) * a(n), are:
  n    a(n)    10^(25-n) * a(n)
  --   ----    -------------------------
   1     1     1000000000000000000000000
   2     2      200000000000000000000000
   3     3       30000000000000000000000
   4     4        4000000000000000000000
   5     5         500000000000000000000
   6     6          60000000000000000000
   7     7           7000000000000000000
   8     8            800000000000000000
   9     9             90000000000000000
  10   100            100000000000000000
  11    10              1000000000000000
  12    11               110000000000000
  13    12                12000000000000
  14    13                 1300000000000
  15    14                  140000000000
  16    15                   15000000000
  17    16                    1600000000
  18    17                     170000000
  19    18                      18000000
  20    19                       1900000
  21  1000                      10000000
  22    20                         20000
  23    21                          2100
  24    22                           220
  25    23                            23
The terms on the third column can be summed without carry in decimal base.
		

Crossrefs

Cf. A298359.

Programs

  • PARI
    See Links section.