A278948 Numbers such that the sum of the reverse of their aliquot parts is equal to the reverse of the sum of their aliquot parts.

4, 6, 8, 9, 10, 15, 21, 25, 49, 1261, 2449, 2701, 2881, 3006, 7486, 9265, 21583, 21809, 22663, 22987, 23707, 23711, 24257, 24613, 24797, 25021, 25217, 25283, 25807, 26123, 26167, 27331, 28199, 28417, 28841, 29143, 29503, 29747, 29987, 30227, 31133, 31313, 31459

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Example

Aliquot parts of 3006 are 1, 2, 3, 6, 9, 18, 167, 334, 501, 1002, 1503. The sum of their reverse is 1 + 2 + 3 + 6 + 9 + 81 + 761 + 433 + 105 + 2001 + 3051 = 6453. The sum of aliquot parts is sigma(3006) - 3006 = 3546 whose reverse is 6453.

Maple

with(numtheory): T:=proc(w) local x, y, z; x:=0; y:=w;
for z from 1 to ilog10(w)+1 do x:=10*x+(y mod 10); y:=trunc(y/10); od; x; end:
P:= proc(q) local a, b, c, k, n; for n from 1 to q do if not isprime(n) then
c:=0; a:=sort([op(divisors(n))]); for k from 1 to nops(a)-1 do c:=c+T(a[k]); od;
if T(sigma(n)-n)=c then print(n); fi; fi; od; end: P(10^9);

Crossrefs

Cf. A001065, A203605.

Sequence in context: A062115 A141613 A072362 * A084988 A202265 A004716

Adjacent sequences: A278945 A278946 A278947 * A278949 A278950 A278951

Keyword

nonn,base,easy

Author

Paolo P. Lava, Dec 02 2016

Status

approved