A084831 Numbers n such that sum of odd divisors and sum of even divisors are both palindromic.

1, 2, 3, 4, 5, 6, 7, 43, 81, 86, 162, 201, 205, 211, 221, 241, 251, 271, 281, 325, 333, 344, 365, 422, 433, 443, 463, 482, 489, 519, 559, 633, 650, 685, 730, 793, 803, 827, 857, 866, 877, 886, 887, 1419, 1505, 1841, 2021, 2111, 2221, 2305, 2441, 2551, 2561, 2611

Offset: 1

Author

Jason Earls, Jun 05 2003

Keywords

• base
• nonn

Comments

Primes of form 2*10^n + R(n) (A056700) and 2/9*(-1+10^n)-1 (A084832) are members.

Examples

			a(11)=162 because sum of even divisors is 242 and sum of odd divisors is 121.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000593, A056700, A084832.

Programs

Mathematica

sodQ[n_]:=Module[{dn=Divisors[n],o,e},o=IntegerDigits[Total[Select[ dn,OddQ]]]; e=IntegerDigits[Total[Select[dn,EvenQ]]]; o== Reverse[o] && e==Reverse[e]]; Select[Range[3000],sodQ] (* Harvey P. Dale, Feb 27 2013 *)