OFFSET
0,3
EXAMPLE
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29
Delete even occurrences of digit 0 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,1~,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29
Delete even occurrences of digit 1 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,12,~3,14,~5,16,~7,18,~9,20,21,22,23,24,25,26,27,28,29
Delete even occurrences of digit 2 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~3,14,~5,16,~7,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 3 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,14,~5,16,~7,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 4 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~5,16,~7,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 5 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~~,16,~7,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 6 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~~,1~,~7,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 7 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~~,1~,~~,18,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 8 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~~,1~,~~,1~,~9,20,~1,2~,23,~4,25,~6,27,~8,29
Delete even occurrences of digit 9 (replaced by ~): 0,1,2,3,4,5,6,7,8,9,~~,1~,1~,~~,1~,~~,1~,~~,1~,~~,20,~1,2~,23,~4,25,~6,27,~8,29
Sequence defined by numbers left: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 1, 1, 1, 1, 20, 1, 2, 23, 4, 25, 6, 27, 8, 29,....
MAPLE
A174210aux := proc(n) option remember; local f, i, dgs ; if n < 0 then return [seq(0, i=0..9)] ; elif n = 0 then return [1, seq(0, i=1..9)] ; else f := procname(n-1) ; for dgs in convert(n, base, 10) do i := op(dgs+1, f) ; f := subsop(dgs+1=i+1, f) ; end do: f ; end if; end proc:
Lton := proc(L, b) add( op(i, L)*b^(i-1), i=1..nops(L)) ; end proc:
A174210 := proc(n) local dgs, f, d; dgs := convert(n, base, 10) ; f := A174210aux(n-1) ; for i from nops(dgs) to 1 by -1 do d := op(i, dgs) ; oldd := op(d+1, f) ; if type( 1+oldd, 'even') then dgs := subsop(i=NULL, dgs) ; end if; f := subsop(d+1=oldd+1, f) ; end do: d := Lton(dgs, 10) ; if d=0 and n>0 then return ; else return d; end if; end proc:
seq(A174210(n), n=0..90) ; # R. J. Mathar, Jun 05 2011
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Paolo P. Lava & Giorgio Balzarotti, Mar 15 2010
STATUS
approved