OFFSET
1,3
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(12) = 121 is a term because 121 is a palindrome and its arithmetic derivative 22 is also a palindrome.
MAPLE
ader:= proc(n) local t;
n*add(t[2]/t[1], t=ifactors(n)[2])
end proc:
rev:= proc(n) local L, i;
L:= convert(n, base, 10);
add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
filter:= proc(n) local d;
if n <> rev(n) then return false fi;
d:= ader(n);
d = rev(d)
end proc:
select(filter, [$0..20000]);
PROG
(PARI) ad(n) = vecsum([n/f[1]*f[2]|f<-factor(n+!n)~]); \\ A003415
ispal(q) = my(d=digits(q)); d == Vecrev(d); \\ A002113
isok(q) = ispal(q) && ispal(ad(q)); \\ Michel Marcus, May 25 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, May 23 2023
STATUS
approved