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

1,2

Comments

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

Links

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

Example

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

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 *)

Crossrefs

Cf. A000593, A056700, A084832.

Sequence in context: A004847 A024646 A327733 * A037406 A237344 A024647

Adjacent sequences: A084828 A084829 A084830 * A084832 A084833 A084834

Keyword

base,nonn

Author

Jason Earls, Jun 05 2003

Status

approved