A130224 a(1) = 1; a(n) = a(n-1) + (number of times the digit 1 has appeared in the sequence so far).

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 19, 24, 29, 34, 39, 44, 49, 54, 59, 64, 69, 74, 79, 84, 89, 94, 99, 104, 110, 118, 128, 139, 151, 165, 180, 196, 213, 231, 250, 269, 288, 307, 326, 345, 364, 383, 402, 421, 441, 462

Offset: 1

Author

Eric Angelini, Aug 05 2007

Keywords

• base
• easy
• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Programs

Maple

A130224 := proc(n)
    option remember;
    if n = 1 then
        1;
    else
        a := procname(n-1) ;
        for j from 1 to n-1 do
            for d in convert(procname(j),base,10) do
                if d = 1 then
                    a := a+1 ;
                end if;
            end do:
        end do:
        a ;
    end if;
end proc:
seq(A130224(n),n=1..52) ; # R. J. Mathar, Aug 06 2016

Mathematica

ss={1};s={1};Do[a=ss[[-1]]+Count[s,1];s=Join[s,IntegerDigits[a]];AppendTo[ss,a],{n,2,52}];ss (* James C. McMahon, Feb 08 2025 *)