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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A035321 Sum of composite divisors of n that are not primes nor prime powers. 6
0, 0, 0, 0, 0, 6, 0, 0, 0, 10, 0, 18, 0, 14, 15, 0, 0, 24, 0, 30, 21, 22, 0, 42, 0, 26, 0, 42, 0, 61, 0, 0, 33, 34, 35, 72, 0, 38, 39, 70, 0, 83, 0, 66, 60, 46, 0, 90, 0, 60, 51, 78, 0, 78, 55, 98, 57, 58, 0, 153, 0, 62, 84, 0, 65, 127, 0, 102, 69, 129, 0, 168, 0, 74, 90, 114, 77 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

FORMULA

a(n) = A178637(n) - 1. - Antti Karttunen, Aug 06 2018

MAPLE

pp := array(1..100); for i from 1 to 100 do pp[i] := 0; od: for i from 1 to 25 do for j from 1 to 6 do t1 := ithprime(i)^j; if t1<100 then pp[t1] := 1; fi; od: od: pp[1] := 1; A035321 := proc(n) local i, d, t1, t2; t1 := 0; for d from 1 to n do if n mod d = 0 and pp[d] = 0 then t1 := t1+d; fi; od; t1; end;

MATHEMATICA

Array[ Plus @@ (Select[ Divisors[ # ], (Length[ FactorInteger[ # ] ]>1)& ])&, 80 ]

PROG

(PARI) A035321(n) = sumdiv(n, d, (omega(d)>1)*(d)); \\ Antti Karttunen, Aug 06 2018

CROSSREFS

Cf. A000203, A035322, A023891, A060278.

One less than A178637.

Sequence in context: A282212 A074591 A318877 * A028720 A028663 A028716

Adjacent sequences:  A035318 A035319 A035320 * A035322 A035323 A035324

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Description corrected by Jack Brennen, Mar 28 2001

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 April 23 09:35 EDT 2019. Contains 322385 sequences. (Running on oeis4.)