A088001 -id:A088001 - cp's OEIS frontend

A179937 a(n) is the product of the non-palindromic divisors of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 1, 12, 13, 14, 15, 16, 17, 18, 19, 200, 21, 1, 23, 288, 25, 338, 27, 392, 29, 4500, 31, 512, 1, 578, 35, 7776, 37, 722, 507, 8000, 41, 12348, 43, 1, 675, 1058, 47, 221184, 49, 12500, 867, 17576, 53, 26244, 1, 21952, 1083, 1682, 59

Offset: 1

Jaroslav Krizek, Jan 12 2011

			For n = 20, set of non-palindromic divisors is {10, 20}; a(12) = 10*20 = 200.

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

Cf. A087990, A087991, A088000, A088001, A184392.

Table[Times@@Select[Divisors[n],!PalindromeQ[#]&],{n,60}] (* Harvey P. Dale, May 15 2023 *)

def ispal(n):
    return n==int(str(n)[::-1])
def A179937(n):
    s=1
    for i in range(1, n+1):
        if n%i==0 and not ispal(i):
            s*=i
    return s # Indranil Ghosh, Feb 10 2017

a(n) = A007955(n) / A184392(n).

More terms from Indranil Ghosh, Feb 10 2017

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

Original entry on oeis.org

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

Jaroslav Krizek, Jan 12 2011

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

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

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

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 *)

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

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

More terms from Harvey P. Dale, Jan 21 2011

cp's OEIS Frontend

A179937 a(n) is the product of the non-palindromic divisors of n.

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