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.

Showing 1-2 of 2 results.

A193413 Valley numbers.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 202, 212, 222, 303, 313, 323, 333, 404, 414, 424, 434, 444, 505, 515, 525, 535, 545, 555, 606, 616, 626, 636, 646, 656, 666, 707, 717, 727, 737, 747, 757, 767, 777, 808, 818, 828, 838, 848, 858, 868, 878, 888, 909, 919, 929, 939, 949, 959, 969, 979, 989, 999, 1001
Offset: 1

Views

Author

Jaroslav Krizek, Jul 25 2011

Keywords

Comments

For n > 10 the structure of digits represents a valley. The first digit is equal to the last digit (1 - 9). The first digits are in nonincreasing order. The last digits are in nondecreasing order. The numbers may have more than one smallest digit. Sequence is infinite.
Superset of crater numbers (A193409) and A193412.
See valley numbers in base 2 (A193414 and A193415).

Examples

			Illustration using 6543333346:
  6 . . . . . . . . 6
  . 5 . . . . . . . .
  . . 4 . . . . . 4 .
  . . . 3 3 3 3 3 . .

Crossrefs

Cf. A110785, A193409, A193412, A193414, A193415.
Cf. A134970. - Omar E. Pol, Aug 05 2011

Extensions

More terms extended by definition by Jaroslav Krizek, Jul 27 2011

A193412 1..9 followed by the canyon numbers A134970.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 101, 202, 212, 303, 313, 323, 404, 414, 424, 434, 505, 515, 525, 535, 545, 606, 616, 626, 636, 646, 656, 707, 717, 727, 737, 747, 757, 767, 808, 818, 828, 838, 848, 858, 868, 878, 909, 919, 929, 939, 949, 959, 969, 979, 989, 2012
Offset: 1

Views

Author

Jaroslav Krizek, Jul 25 2011

Keywords

Comments

For n > 9 the structure of digits represents an abyss. The first digit is equal to the last digit (1 - 9). The first digits are in decreasing order. The last digits are in increasing order. The numbers only have one smallest digit. This sequence is finite. The final term is 9876543210123456789.
Superset of crater numbers (A193409). Subset of valley numbers (A193413).

Examples

			Illustration using 654356:
  6  .  .  .  .  6
  .  5  .  .  5  .
  .  .  4  .  .  .
  .  .  .  3  .  .

Crossrefs

Cf. A193409, A193413, A134970.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.