OFFSET
1,2
COMMENTS
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
Select[Range[2000], ! PrimeQ[#] && First[IntegerDigits[#]] == 1 && Last[IntegerDigits[#]] == 1 &] (* Vladimir Joseph Stephan Orlovsky, Feb 26 2012 *)
Join[{1}, Select[Range[2000], CompositeQ[#]&&NumberDigit[#, 0] == NumberDigit[ #, IntegerLength[ #]-1]==1&]] (* Harvey P. Dale, Aug 01 2021 *)
PROG
(Haskell)
a208260 n = a208260_list !! (n-1)
a208260_list = filter ((== 0) . a010051') a208259_list
-- Reinhard Zumkeller, Jul 16 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Feb 24 2012
STATUS
approved