OFFSET
1,1
COMMENTS
a(n) = A052191(n) / n.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
a(23)=99 since 23*99=2277 and all the digits of 2277 have a neighboring digit which is the same.
MATHEMATICA
isol[n_ ] := Module[{}, L={11}~Join~IntegerDigits[n ]~Join~{11}; l=Length[L ]; Apply[And, Table[L[[i ] ]==L[[i-1 ] ]||L[[i ] ]==L[[i+1 ] ], {i, 2, l-1} ] ] ] a[n_ ] := a[n ]=Module[{}, m=0; While[Not[isol[m ] ], m=m+n ]; m ] Table[a[i ], {i, 1, 100} ]/Range[100 ]
PROG
(Haskell)
import Data.List (group, findIndex)
import Data.Maybe (fromJust)
a052192 n = fromJust $
findIndex ((> 1) . minimum . map length . group . show) $ [0, n..]
-- Reinhard Zumkeller, Sep 15 2011
CROSSREFS
KEYWORD
AUTHOR
Erich Friedman, Jan 28 2000
STATUS
approved