OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..55
EXAMPLE
The palindromic composite number 77 has palindromic composite index 55 in A002808. So 77 belongs to the present sequence.
MATHEMATICA
composite[n_]:=FixedPoint[n+PrimePi[#]+1&, n+PrimePi[n]+1];
indices=Select[Range[10^6], CompositeQ[#]&&PalindromeQ[#]&&PalindromeQ[composite[#]]&];
terms=composite/@indices (*"composite" function defined by Robert G. Wilson v at A002808*)
CROSSREFS
KEYWORD
nonn,base,hard
AUTHOR
Ivan N. Ianakiev, Dec 21 2019
EXTENSIONS
a(1)-a(32) from Daniel Suteu, Dec 21 2019
STATUS
approved