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A227228 Palindromes greater than 10 whose sum of proper divisors is also a palindrome greater than 10. 1
333, 646, 656, 979, 1001, 3553, 10801, 11111, 18581, 31713, 34943, 48484, 57375, 95259, 99099, 158851, 262262, 569965, 1173711, 1216121, 1399931, 1439341, 1502051, 1925291, 3203023, 3436343, 3659563, 3662663, 3803083, 3888883, 5185815, 5352535, 5893985 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The palindromic primes (A002385) (whose sum of proper divisors is 1) are not included in this sequence.

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..260 (terms < 10^14)

EXAMPLE

10801 = 1543*7*1 and 1543 + 7 + 1 = 1551 (a palindrome). So, 10801 is a member of this sequence.

PROG

(Python)

from sympy import divisors

def rev(n):

..r = ''

..for i in str(n):

....r = i + r

..return int(r)

for i in range(10**6):

..s = sum(divisors(i))-i

..if rev(i) == i and s > 10 and rev(s) == s:

....print(i, end=', ')

# simplified by Derek Orr, Oct 16 2014

CROSSREFS

Cf. A002113, A001065, A002385.

Sequence in context: A158081 A248062 A056089 * A066801 A066349 A043503

Adjacent sequences:  A227225 A227226 A227227 * A227229 A227230 A227231

KEYWORD

nonn,base

AUTHOR

Derek Orr, Sep 19 2013

STATUS

approved

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Last modified October 17 07:39 EDT 2021. Contains 348048 sequences. (Running on oeis4.)