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A255732
Rhonda numbers in vigesimal number system.
15
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
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.
Column k=11 of A291925.
Sequence in context: A238141 A058954 A205258 * A338166 A353807 A326236
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Mar 05 2015
STATUS
approved