A079342 Integers n that divide LS(n), where LS is the "Look and Say" function (A045918).

1, 2, 5, 10, 22, 32, 62, 91, 183, 188, 190, 196, 258, 276, 330, 671, 710, 1130, 1210, 1570, 2644, 2998, 3292, 4214, 17055, 20035, 53015, 70315, 101010, 108947, 199245, 233606, 309665, 323232, 356421, 483405, 626262, 919191, 1743599

Offset

1,2

Links

Table of n, a(n) for n=1..39.

Example

E.g. LS(1)=11, LS(2)=12, LS(10)=1110, LS(188)=1128 etc. and in each case LS(n) is a multiple of n.
122918=0 mod 2998, so 2998 is in the sequence.
But 13 == 1 mod 3, so 3 is not in the sequence.

Maple

# Implementation by R. J. Mathar, May 08 2019:
A045918 := proc(n)
    local a, f, pd, dgs, i ;
    a := [] ;
    f := 0 ;
    pd := -1 ;
    dgs := convert(n, base, 10) ;
    for i from 1 to nops(dgs) do
        if op(-i, dgs) <> pd then
            if pd >= 0 then
                a := [op(a), f, pd] ;
            end if;
            pd := op(-i, dgs) ;
            f := 1 ;
        else
            f:= f+1 ;
        end if;
    end do:
    a := [op(a), f, pd] ;
    digcatL(%) ;
end proc:
isA079342 := proc(n)
    simplify( modp(A045918(n) , n) = 0 ) ;
end proc:
for n from 1 to 30000 do
    if isA079342(n) then
        print(n) ;
    end if;
end do:

Crossrefs

Cf. A056815, A005150, A079562.

Cf. A152957. - David Wasserman, Dec 15 2008

Sequence in context: A278441 A323939 A110744 * A034456 A272080 A002512

Adjacent sequences: A079339 A079340 A079341 * A079343 A079344 A079345

Keyword

base,nonn,easy

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 13 2003

Status

approved