A073956 - OEIS

A073956

Palindromes whose sum of anti-divisors is palindromic.

1, 2, 3, 4, 5, 6, 8, 9, 242, 252, 323, 434, 727, 4774, 32223, 42024, 43234, 46864, 64946, 70607, 4855584, 4942494, 6125216, 6265626, 149939941, 188737881, 241383142, 389181983, 470212074, 27685458672, 42685658624, 45625352654, 61039793016

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

See A066272 for definition of anti-divisor.

Subsequence of A002113. - Michel Marcus, Aug 10 2014

LINKS

Table of n, a(n) for n=1..33.

PROG

(Python)

from itertools import chain

def is_palindrome(x):

....return x == x[::-1]

A073956 = sorted([n for n in chain(map(lambda x:int(str(x)+str(x)[::-1]), range(1, 10**2)), map(lambda x:int(str(x)+str(x)[-2::-1]), range(1, 10**3))) if is_palindrome(str(int(sum([d for d in range(2, n, 2) if n%d and not 2*n%d]))+int(sum([d for d in range(3, n, 2) if n%d and 2*n%d in [d-1, 1]]))))]) # Chai Wah Wu, Aug 09 2014

CROSSREFS

Cf. A002113, A066272, A066417.

Sequence in context: A203616 A274049 A038101 * A360414 A270193 A039266

Adjacent sequences: A073953 A073954 A073955 * A073957 A073958 A073959

KEYWORD

base,nonn

AUTHOR

Jason Earls, Sep 03 2002

EXTENSIONS

a(21)-a(33) from Donovan Johnson, Mar 30 2010

STATUS

approved