A072960 Numbers using only the curved digits 0, 3, 6, 8 and 9.

0, 3, 6, 8, 9, 30, 33, 36, 38, 39, 60, 63, 66, 68, 69, 80, 83, 86, 88, 89, 90, 93, 96, 98, 99, 300, 303, 306, 308, 309, 330, 333, 336, 338, 339, 360, 363, 366, 368, 369, 380, 383, 386, 388, 389, 390, 393, 396, 398, 399, 600, 603, 606, 608, 609, 630, 633, 636, 638

Offset: 1

Author

Michael Joseph Halm, Aug 13 2002

Keywords

• easy
• nonn
• base

Comments

Exponential density 0.69897... = log 5/log 10. A 10-automatic sequence. - Charles R Greathouse IV, Jul 22 2012

References

• M. J. Halm, Three Boxes, Puzzle-M Magazine (Apr. 1987).

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..1000
• Index entries for 10-automatic sequences.

Programs

Mathematica

f[n_] := Block[{id = IntegerDigits[n], curve = {0, 3, 6, 8, 9}}, If[ Union[ Join[id, curve]] == curve, True, False]]; Select[ Range[0, 240], f[ # ] & ]
FromDigits/@Tuples[{0,3,6,8,9},3] (* Harvey P. Dale, May 01 2018 *)

PARI

isok(n)= my(d = Set(digits(n))); for (k=1, #d, if (vecsearch([1,2,4,5,7],d[k]), return (0))); 1; \\ Michel Marcus, May 11 2016

Python

from itertools import product
A072960_list = [0] + [int(a+''.join(b)) for l in range(5) for a in '3689' for b in product('03689',repeat=l)] # Chai Wah Wu, May 12 2016

Extensions

Corrected by Rick L. Shepherd, Aug 13 2002

Offset corrected by Arkadiusz Wesolowski, Aug 15 2011