A130231 a(1) = 3; a(n) = a(n-1) + (number of times the digit 3 has appeared in the sequence so far).

3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19, 21, 23, 26, 29, 32, 36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, 91, 96, 101, 106, 111, 116, 121, 126, 131, 137, 144, 151, 158, 165, 172, 179, 186, 193, 201, 209, 217, 225, 233, 243, 254, 265, 276, 287, 298, 309, 321, 334

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Maple

A130231 := proc(n)
    option remember;
    if n = 1 then
        3;
    else
        a := procname(n-1) ;
        for j from 1 to n-1 do
            for d in convert(procname(j), base, 10) do
                if d = 3 then
                    a := a+1 ;
                end if;
            end do:
        end do:
        a ;
    end if;
end proc:
seq(A130231(n), n=1..80) ; # R. J. Mathar, Aug 06 2016

Crossrefs

Sequence in context: A026447 A194378 A283810 * A333491 A304816 A298005

Adjacent sequences: A130228 A130229 A130230 * A130232 A130233 A130234

Keyword

base,easy,nonn

Author

Eric Angelini, Aug 05 2007

Extensions

Corrected by R. J. Mathar, Aug 06 2016

Status

approved