A255732 Rhonda numbers in vigesimal number system.

1815, 11050, 15295, 21165, 22165, 30702, 34510, 34645, 42292, 44165, 52059, 53416, 65945, 78430, 80712, 84251, 84835, 86591, 112608, 146055, 148144, 156284, 175419, 178350, 194590, 200655, 201825, 202664, 204085, 209095, 209550, 211250, 212346, 212850

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) = 1815 = 4*20^2 + 10*20^1 + 15*20^0 = 3*5*11*11,
with 4 * 10 * 15 = 20 * (3+5+11+11) = 600;
a(10) = 44165 = 5*20^3 + 10*20^2 + 8*20^1 + 5*20^0 = 5*11*11*73,
with 5 * 10 * 8 * 5 = 20 * (5+11+11+73) = 2000.
		

Links

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

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), A255736 (base 30), A255731 (base 60), see also A255872.

Cf. A001414, A027746.

Column k=11 of A291925.

Programs

Haskell

a255732 n = a255732_list !! (n-1)
a255732_list = filter (rhonda 20) $ iterate z 1 where
   z x = 1 + if r < 29 then x else 30 * z x' where (x', r) = divMod x 30
-- Function rhonda as in A099542.