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

1,1

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, Vigesimal

Example

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.

Prog

(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.

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.

Sequence in context: A238141 A058954 A205258 * A338166 A353807 A326236

Adjacent sequences: A255729 A255730 A255731 * A255733 A255734 A255735

Keyword

nonn,base

Author

Reinhard Zumkeller, Mar 05 2015

Status

approved