login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A192279 Anti-hypersigma(n): sum of the anti-divisors of n plus the recursive sum of the anti-divisors of the anti-divisors until 2 is reached. 1
2, 5, 7, 9, 19, 17, 17, 40, 33, 37, 45, 40, 67, 49, 89, 96, 65, 88, 71, 134, 127, 91, 189, 120, 187, 170, 91, 166, 151, 219, 243, 164, 261, 140, 315, 392, 233, 310, 247, 374, 245, 150, 461, 280, 285, 347, 407, 468, 215, 538, 515, 234, 565, 422, 609, 532, 495 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Similar to A191150 but using anti-divisors. The recursion is stopped when 2 is reached because 2 has no anti-divisors.

LINKS

Paolo P. Lava, Table of n, a(n) for n = 3..5000

EXAMPLE

n=14 -> anti-divisors are 3,4,9. We start with 3+4+9=16.

Now for 3, 4 and 9 we repeat the procedure:

3-> 2 -> no anti-divisors. To add: 2.

4-> 3 -> 2 -> no anti-divisors. To add: 3+2=5.

9-> 2,6. To add: 2+6=8.

--- 2 -> no anti-divisors.

--- 6 -> 4 -> 3 -> 2 -> no anti-divisors. To add: 4+3+2=9.

Total is 16+2+5+8+9=40.

MAPLE

with(numtheory);

P:=proc(n)

local a, b, c, k, s;

a:={};

for k from 2 to n-1 do if abs((n mod k)- k/2) < 1 then a:=a union {k}; fi;

od;

b:=nops(a); c:=op(a); s:=0;

if b>1 then

  for k from 1 to b do s:=s+c[k]; od;

else s:=c;

fi;

b:=nops(a); c:=(sort([op(a)]));

for k from 1 to b do if c[k]>2 then s:=s+P(c[k]); fi; od;

s;

end:

Antihps:=proc(i)

local n;

for n from 1 to i do print(P(n)); od;

end:

CROSSREFS

Cf. A066272, A191150.

Sequence in context: A211167 A083272 A115906 * A286356 A086422 A046880

Adjacent sequences:  A192276 A192277 A192278 * A192280 A192281 A192282

KEYWORD

nonn,easy

AUTHOR

Paolo P. Lava, Jul 13 2011

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 16:00 EDT 2019. Contains 321292 sequences. (Running on oeis4.)