A255731 Rhonda numbers in sexagesimal number system.

3348, 3510, 6750, 17430, 18750, 18876, 18944, 19475, 20564, 21312, 26550, 28280, 37230, 38396, 43940, 48042, 77770, 88270, 91224, 97470, 108882, 111403, 120046, 123630, 181996, 182646, 235467, 253460, 260429, 264735, 278675, 289161, 295960, 296055, 306642

Offset

1,1

Comments

See A099542 for definition of Rhonda numbers and for more links.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Rhonda Number

Wikipedia, Sexagesimal

Example

a(1) = 3348 = 55 * 60^1 + 48 * 60^0 = 2*2*3*3*3*31,
with 55 * 48 = 60 * (2+2+3+3+3+31) = 2640;
a(10) = 21312 = 5*60^2 + 55*60^1 + 12*60^0 = 2*2*2*2*2*2*3*3*37,
with 5 * 55 * 12 = 60 * (2+2+2+2+2+2+3+3+37) = 3300.

Prog

(Haskell)
a255731 n = a255731_list !! (n-1)
a255731_list = filter (rhonda 60) $ iterate z 1 where
   z x = 1 + if r < 59 then x else 60 * z x' where (x', r) = divMod x 60
-- Function rhonda as in A099542.

Crossrefs

Cf. Rhonda numbers to other bases: A100968 (base 4), A100969 (base 6), A100970 (base 8), A100973 (base 9), A099542 (base 10), A100971 (base 12), A100972 (base 14), A100974 (base 15), A100975 (base 16), A255735 (base 18), A255732 (base 20), A255736 (base 30).

Cf. A001414, A027746.

Column k=42 of A291925.

Sequence in context: A054356 A358312 A348525 * A204884 A204880 A151601

Adjacent sequences: A255728 A255729 A255730 * A255732 A255733 A255734

Keyword

nonn,base

Author

Reinhard Zumkeller, Mar 05 2015

Status

approved