This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A073956 #26 Dec 30 2024 15:12:11 %S A073956 1,2,3,4,5,6,8,9,242,252,323,434,727,4774,32223,42024,43234,46864, %T A073956 64946,70607,4855584,4942494,6125216,6265626,149939941,188737881, %U A073956 241383142,389181983,470212074,27685458672,42685658624,45625352654,61039793016 %N A073956 Palindromes whose sum of anti-divisors is palindromic. %C A073956 See A066272 for definition of anti-divisor. %H A073956 Sean A. Irvine, <a href="/A073956/b073956.txt">Table of n, a(n) for n = 1..45</a> %o A073956 (Python) %o A073956 from itertools import chain %o A073956 def is_palindrome(x): %o A073956 return x == x[::-1] %o A073956 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 %Y A073956 Cf. A002113 (palindromes), A066272, A066417. %K A073956 base,nonn %O A073956 1,2 %A A073956 _Jason Earls_, Sep 03 2002 %E A073956 a(21)-a(33) from _Donovan Johnson_, Mar 30 2010