login
A115656
Both n and the reverse of n are powerful(1) numbers (A001694).
5
1, 4, 8, 9, 27, 72, 100, 121, 144, 169, 343, 400, 441, 484, 576, 675, 676, 800, 900, 961, 1000, 1089, 1331, 1800, 2700, 3087, 4000, 7200, 7803, 8000, 9000, 9801, 10000, 10201, 10404, 10609, 12100, 12321, 12544, 12769, 14400, 14641, 14884
OFFSET
1,2
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..6228
EXAMPLE
9801=3^4*11^2 and 1089=3^2*11^2.
PROG
(PARI) is(n)=ispowerful(n) && ispowerful(subst(Polrev(digits(n)), 'x, 10)) \\ Charles R Greathouse IV, Sep 16 2014
(PARI) has(n)=ispowerful(subst(Polrev(digits(n)), 'x, 10))
list(lim)=my(v=List(), t, t2); for(m=1, lim^(1/3), t=m^3; for(n=1, sqrtint(lim\t), if(has(t2=t*n^2), listput(v, t2)))); Set(v) \\ Charles R Greathouse IV, Sep 16 2014
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Giovanni Resta, Jan 28 2006
STATUS
approved