A184392 a(n) is the product of palindromic divisors of n.

1, 2, 3, 8, 5, 36, 7, 64, 27, 10, 11, 144, 1, 14, 15, 64, 1, 324, 1, 40, 21, 484, 1, 1152, 5, 2, 27, 56, 1, 180, 1, 64, 1089, 2, 35, 1296, 1, 2, 3, 320, 1, 252, 1, 85184, 135, 2, 1, 1152, 7, 10, 3, 8, 1, 324, 3025, 448, 3, 2, 1, 720, 1, 2, 189, 64, 5, 18974736, 1, 8, 3, 70, 1, 10368, 1, 2, 15, 8, 5929, 36, 1, 320, 27, 2, 1, 1008, 5, 2, 3, 59969536, 1, 1620, 7, 8, 3, 2, 5, 1152, 1, 14, 970299, 40

Offset: 1

Author

Jaroslav Krizek, Jan 12 2011

Keywords

• nonn
• base

Examples

			For n = 20, set of palindromic divisors is {1, 2, 4, 5}; a(12) = 1*2*4*5 = 40.
		

Links

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

Crossrefs

Cf. A007955, A087990, A087991, A088000, A088001, A179937.

Programs

Mathematica

palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]; f[n_]:=Times@@Select[Divisors[n],palQ]; Table[f[n],{n,100}]  (* Harvey P. Dale, Jan 21 2011 *)

Python

def ispal(n):
    return n==int(str(n)[::-1])
def A184392(n):
    s=1
    for i in range(1, n+1):
        if n%i==0 and ispal(i):
             s*=i
    return s # Indranil Ghosh, Feb 10 2017

Formula

a(n) = A007955(n) / A179937(n).

Extensions

More terms from Harvey P. Dale, Jan 21 2011