OFFSET
1,3
EXAMPLE
MAPLE
A006530 := proc(n) if n = 1 then 1; else numtheory[factorset](n) ; max(op(%)) ; end if; end proc:
isA002113 := proc(n) dgs := convert(n, base, 10) ; for i from 1 to nops(dgs) do if op(i, dgs) <> op(-i, dgs) then return false; end if; end do: return true; end proc:
isA002385 := proc(n) isprime(n) and isA002113(n) ; end proc:
A180613 := proc(n) a := 0 ; for i from 1 to n do if isA002385(A006530(i)) then a := a+1 ; end if; end do: a; end proc:
seq(A180613(n), n=1..40) ; # R. J. Mathar, Sep 25 2010
CROSSREFS
KEYWORD
base,nonn,less
AUTHOR
Giovanni Teofilatto, Sep 12 2010
EXTENSIONS
Definition clarified by R. J. Mathar, Sep 25 2010
STATUS
approved