A252664 Minimal nontrivial undulant (A046075) divisible by n, or 0 if no undulant is divisible by n.

101, 202, 141, 212, 505, 252, 161, 232, 171, 1010, 121, 252, 494, 252, 525, 272, 272, 252, 171, 2020, 252, 242, 161, 696, 525, 494, 2727, 252, 232, 3030, 434, 3232, 363, 272, 525, 252, 3737, 494, 585, 4040, 656, 252, 989, 484, 585, 414, 141, 4848, 343, 5050

Offset

1,1

Comments

Undulants are numbers are of the form ababab..... with a and b distinct digits (base 10, a nonzero). An undulate is nontrivial if it has at least 3 digits. - Danny Rorabaugh, Apr 22 2015

Links

Reiner Moewald, Table of n, a(n) for n = 1..499

Example

505 is the least entry of A046075 that is divisible by 5, so a(5) = 505. Since an undulant cannot end in 00, a(100)=0. - Danny Rorabaugh, Apr 22 2015

Prog

(Python)
feld = []
for n in range(3, 500):
...for a in range(1, 10):
......for b in range(10):
.........if a != b:
............z_string = ""
............for pos in range(n):
...............if pos % 2 == 0:
..................z_string = z_string + str(a)
...............else:
..................z_string = z_string + str(b)
............z = int(z_string)
............feld.append(z)
feld_length = len(feld)
for z in range (1, 150):
...start = 0
...while start < feld_length and feld[start] % z != 0:
......start = start + 1
...if start < feld_length:
......print(z, feld[start])

Crossrefs

Cf. A046075.

Sequence in context: A044714 A158128 A162670 * A134970 A081365 A138131

Adjacent sequences: A252661 A252662 A252663 * A252665 A252666 A252667

Keyword

nonn,base

Author

Reiner Moewald, Mar 22 2015

Status

approved