A088000 a(n) is the sum of the palindromic divisors of n.

1, 3, 4, 7, 6, 12, 8, 15, 13, 8, 12, 16, 1, 10, 9, 15, 1, 21, 1, 12, 11, 36, 1, 24, 6, 3, 13, 14, 1, 17, 1, 15, 48, 3, 13, 25, 1, 3, 4, 20, 1, 19, 1, 84, 18, 3, 1, 24, 8, 8, 4, 7, 1, 21, 72, 22, 4, 3, 1, 21, 1, 3, 20, 15, 6, 144, 1, 7, 4, 15, 1, 33, 1, 3, 9, 7, 96, 12, 1, 20, 13, 3, 1, 23, 6, 3

Offset: 1

Author

Labos Elemer, Oct 14 2003

Keywords

• base
• nonn

Examples

			n=14: a(14)=1+2+7=10;
n=101: a(101)=1+101=102;
		

Links

• Indranil Ghosh, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A062687 (all divisors are palindromic), A087990 (number of palindromic divisors).

Programs

Maple

A088000 := proc(n)
    a := 0 ;
    for d in numtheory[divisors](n) do
        if isA002113(d) then
            a := a+d ;
        end if;
    end do;
    a ;
end proc:
seq(A088000(n),n=1..100) ; # R. J. Mathar, Sep 09 2015

Mathematica

Table[Plus @@ Select[Divisors[k], Reverse[x = IntegerDigits[#]] == x &], {k, 86}] (* Jayanta Basu, Aug 12 2013 *)

PARI

a(n) = sumdiv(n, d, my(dd=digits(d)); if (Vecrev(dd) == dd, d)); \\ Michel Marcus, Apr 06 2020

Python

def ispal(n):
    return n==int(str(n)[::-1])
def A088000(n):
    s=0
    for i in range(1, n+1):
        if n%i==0 and ispal(i):
             s+=i
    return s
print([A088000(n) for n in range(1,30)]) # Indranil Ghosh, Feb 10 2017