login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A213239 Numbers n such that sum of digits of n = sum of digits of anti-divisors of n. 2
5, 8, 64, 691, 1779, 2851, 6361, 9066, 9606, 9771, 10789, 10996, 18996, 21481, 22569, 27529, 27691, 31516, 36709, 36776, 42649, 48651, 53296, 56586, 58749, 60369, 64794, 72889, 76754, 78766, 79374, 79896, 80989, 86596, 90606, 90879, 92766, 96171, 98979, 108529 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
Sum of digits of 1779 is 1+7+7+9=24.
Anti-divisors of 1779 are 2, 6, 1186 and their digits’ sum is 2+6+1+1+8+6=24.
MAPLE
with(numtheory);
A213239:=proc(q)
local a, b, c, d, k, n;
for n from 1 to q do
a:=0; b:=0;
for k from 2 to n-1 do
if abs((n mod k)-k/2)<1 then
c:=k; while c>0 do b:=b+(c mod 10); c:=trunc(c/10); od; fi; od;
c:=n; d:=0; while c>0 do d:=d+(c mod 10); c:=trunc(c/10); od;
if b=d then print(n); fi; od; end:
A213239(100000);
PROG
(Python)
[n for n in range(1, 10**5) if sum([sum([int(x) for x in str(d)]) for d in range(2, n) if n % d and 2*n % d in [d-1, 0, 1]]) == sum([int(x) for x in str(n)])] # Chai Wah Wu, Aug 08 2014
CROSSREFS
Sequence in context: A342195 A132050 A250067 * A123819 A286076 A302651
KEYWORD
nonn,base
AUTHOR
Paolo P. Lava, Jun 07 2012
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 16:28 EDT 2024. Contains 371254 sequences. (Running on oeis4.)