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

1,2

Links

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

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 *)

Crossrefs

Sequence in context: A236686 A246084 A260768 * A017903 A005711 A322856

Adjacent sequences: A130221 A130222 A130223 * A130225 A130226 A130227

Keyword

base,easy,nonn,changed

Author

Eric Angelini, Aug 05 2007

Status

approved