OFFSET
1,2
COMMENTS
a(1)=1 is included because 1 has an empty factorization (either no exponents, or all of them are zero), which thus is also a palindrome.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..1200
FORMULA
a(1)=1, and for n > 1, a(n) = 2 * A241912(n-1).
MATHEMATICA
f[n_] := If[n == 1, {0}, Function[f, ReplacePart[Table[0, {PrimePi[f[[-1, 1]]]}], #] &@ Map[PrimePi@ First@ # -> Last@ # &, f]]@ FactorInteger@ n]; g[w_List] := Times @@ Flatten@ MapIndexed[Prime[#2]^#1 &, w]; Select[Range@ 336, g@ f@ # == g@ Reverse@ f@ # &] (* Michael De Vlieger, Aug 27 2016 *)
PROG
(Scheme, with Antti Karttunen's IntSeq-library)
;; Alternatively:
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 20 2014
STATUS
approved