OFFSET
1,2
COMMENTS
EXAMPLE
a(18) = 40 (base 10) is in the sequence because 40 (base 10) = 130 (base 5) which has an odd number (1) of 1's ; whereas 41 is not in the sequence because 41 (base 10) = 131 (base 5) has an even number (2) of 1's.
MAPLE
isA137469 := proc(n) local a, d ; a := 0 ; for d in convert(n, base, 5) do if d =1 then a := a+1 ; fi ; od; RETURN( a mod 2 = 1 ) ; end: for n from 1 to 400 do if isA137469(n) then printf("%d, ", n) ; fi ; od: # R. J. Mathar, Apr 21 2008
MATHEMATICA
Select[Range[200], OddQ[DigitCount[ #, 5][[1]]] &] - Stefan Steinerberger, Apr 21 2008
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Apr 20 2008
EXTENSIONS
More terms from R. J. Mathar and Stefan Steinerberger, Apr 21 2008
STATUS
approved