OFFSET
1,4
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..50000
Pe, J. The Picture-Perfect Numbers
FORMULA
EXAMPLE
The proper divisors of 20 are 1,2,4,5,10, which reversed are 1,2,4,5,1, summing to 13. Therefore a(20) = 13.
MATHEMATICA
f[n_] := FromDigits[Reverse[IntegerDigits[n]]]; g[n_] := Apply[Plus, Map[f, Drop[Divisors[n], -1]]]; Table[g[i], {i, 1, 40}]
Table[Total[IntegerReverse/@Most[Divisors[n]]], {n, 100}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 04 2021 *)
PROG
(Python)
def A069250(n):
....s=0
....for i in range(1, n):
........if n%i==0: s+=int(str(i)[::-1])
....return s # Indranil Ghosh, Feb 10 2017
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Joseph L. Pe, Apr 19 2002
EXTENSIONS
More terms from N. J. A. Sloane, May 19 2013
STATUS
approved