OFFSET
1,1
COMMENTS
Leading zeros as in A006887(4), 26198073 = (26+198+073)^3, are not allowed here.
Is it a coincidence that a(2)^3 = 91125 also verifies sqrt(91125) = 9*sqrt(1125)?
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..239 (terms < 10^12)
NĂºmeros y algo mas, 9 + 11 + 25 = 91125^(1/3) etc, post on facebook.com, Sep 30 2019.
EXAMPLE
5 + 1 + 2 = 512^(1/3) = 8,
9 + 11 + 25 = 91125^(1/3) = 45,
418 + 1062 + 131 = (4181062131)^(1/3) = 1611, ...
PROG
(PARI) is(n, Ln=A055642(n), n3=n^3, Ln3=A055642(n3))={my(ab, c); for(Lc=Ln3-2*Ln, Ln, [ab, c]=divrem(n3, 10^Lc); n-c<10^(Ln-1) || c < 10^(Lc-1) || for( Lb=Ln3-Ln-Lc, Ln, vecsum(divrem(ab, 10^Lb)) == n-c && ab%10^Lb>=10^(Lb-1)&& return(1)))} \\ A055642(n)=logint(n, 10)+1 = #digits(n)
for( Ln=1, oo, for( n=10^(Ln-1), 10^Ln-1, is(n, Ln)&& print1(n", ")))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Oct 07 2019
EXTENSIONS
a(31)-a(35) from Giovanni Resta, Oct 09 2019
STATUS
approved