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

Author

Reinhard Zumkeller, Mar 05 2015

Keywords

• nonn
• base

Comments

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

Examples

			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.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
• Eric Weisstein's World of Mathematics, Rhonda Number
• Wikipedia, Sexagesimal

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.

Programs

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.