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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A175760 Numbers n such that d(n + d(n)) = d(n), where d(n) is the sum of the distinct primes dividing n. 3
1, 2, 39, 95, 119, 182, 2130, 2183, 2356, 2623, 3059, 3431, 3825, 6680, 9588, 10170, 10679, 11790, 14039, 14111, 15030, 16199, 16762, 16799, 17766, 19669, 22218, 24505, 26352, 26353, 34443, 34765, 34875, 36594, 37843, 39121, 39479, 39697, 42210, 44051, 45346 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sum of the distinct primes dividing n (A008472) sometimes called sopf(n).

d(1) = 0 because 1 has no prime divisors. So 1 is in this sequence because d(1+0) = d(1). - T. D. Noe, Jul 06 2012

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

EXAMPLE

39 is in the sequence because sopf(39) = 16 and sopf(39 + sopf(39)) = sopf(55 ) = 16.

MATHEMATICA

d[n_] := Plus @@ Transpose[FactorInteger[n]][[1]]; Join[{1}, Select[Range[2, 50000], d[# + d[#]] == d[#] &]]

CROSSREFS

Sequence in context: A078733 A201360 A227904 * A080920 A086338 A329552

Adjacent sequences:  A175757 A175758 A175759 * A175761 A175762 A175763

KEYWORD

nonn

AUTHOR

Michel Lagneau, Aug 28 2010

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 December 14 03:31 EST 2019. Contains 329978 sequences. (Running on oeis4.)