A274049 Numbers n such that sum of anti-divisors of n is palindromic.

1, 2, 3, 4, 5, 6, 8, 9, 21, 40, 42, 53, 76, 84, 127, 137, 143, 150, 163, 173, 177, 199, 208, 211, 229, 236, 242, 249, 252, 255, 273, 277, 288, 289, 298, 316, 320, 321, 323, 329, 332, 334, 335, 336, 351, 372, 401, 411, 419, 431, 434, 437, 467, 475, 477, 485, 489, 497

Offset

1,2

Comments

A274028 is a subset of this sequence.

Links

Paolo P. Lava, Table of n, a(n) for n = 1..1300

Example

Anti-divisors of 150 are 4, 7, 12, 13, 20, 23, 43, 60, 100 and their sum is 282 that is palindromic.

Maple

with(numtheory): T:=proc(w) local x, y, z; x:=w; y:=0; for z from 1 to ilog10(x)+1 do y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:
P:=proc(q) local a, j, k, n; for n from 1 to q do k:=0; j:=n; while j mod 2 <> 1 do
k:=k+1; j:=j/2; od; a:=sigma(2*n+1)+sigma(2*n-1)+sigma(n/2^k)*2^(k+1)-6*n-2;
if T(a)=a then print(n); fi; od; end: P(10^12);

Crossrefs

Cf. A066417, A073956.

Sequence in context: A317676 A039125 A203616 * A038101 A073956 A360414

Adjacent sequences: A274046 A274047 A274048 * A274050 A274051 A274052

Keyword

nonn,base

Author

Paolo P. Lava, Jun 08 2016

Status

approved