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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A075255 a(n) = n - (sum of primes factors of n (with repetition)). 13
 1, 0, 0, 0, 0, 1, 0, 2, 3, 3, 0, 5, 0, 5, 7, 8, 0, 10, 0, 11, 11, 9, 0, 15, 15, 11, 18, 17, 0, 20, 0, 22, 19, 15, 23, 26, 0, 17, 23, 29, 0, 30, 0, 29, 34, 21, 0, 37, 35, 38, 31, 35, 0, 43, 39, 43, 35, 27, 0, 48, 0, 29, 50, 52, 47, 50, 0, 47, 43, 56, 0, 60, 0, 35, 62, 53, 59, 60 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..10000 FORMULA a(n) = n - A001414(n). a(n) = 0 if n is prime or if n = 4. - Alonso del Arte, Jul 31 2018 EXAMPLE a(6) = 1 because 6 = 2 * 3, sopfr(6) = 2 + 3 = 5 and 6 - 5 = 1. MAPLE a:= n-> n-add(i[1]*i[2], i=ifactors(n)[2]): seq(a(n), n=1..100); # Alois P. Heinz, Aug 07 2015 MATHEMATICA Join[{1}, Table[n - Total[Times@@@FactorInteger[n]], {n, 2, 80}]] (* Harvey P. Dale, Sep 20 2011 *) PROG (PARI) A075255(n)=n-sum(i=1, #n=factor(n)~, n[1, i]*n[2, i]) \\ M. F. Hasler, Oct 31 2008 (Magma) [n eq 1 select 1 else n-(&+[p[1]*p[2]: p in Factorization(n)]): n in [1..80]]; // G. C. Greubel, Jan 11 2019 (Sage) [n - sum(factor(n)[j][0]*factor(n)[j][1] for j in range(0, len(factor(n)))) for n in range(1, 80)] # G. C. Greubel, Jan 11 2019 (Python) from sympy import factorint def A075255(n): return n - sum(factorint(n, multiple=True)) # Chai Wah Wu, May 19 2022 CROSSREFS Cf. A001414, A008472, A075254, A075653. Cf. A145834 (= 0 followed by the nonzero terms of this sequence). - M. F. Hasler, Oct 31 2008 Sequence in context: A021815 A238525 A359788 * A135498 A104172 A091408 Adjacent sequences: A075252 A075253 A075254 * A075256 A075257 A075258 KEYWORD nonn AUTHOR Zak Seidov, Sep 10 2002 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.

Last modified April 1 22:19 EDT 2023. Contains 361716 sequences. (Running on oeis4.)