The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A053571 Sum of totient functions over arguments running through numbers unrelated to n. 5
 0, 0, 0, 0, 0, 2, 0, 2, 2, 8, 0, 14, 0, 16, 16, 16, 0, 36, 0, 38, 32, 44, 0, 68, 20, 62, 40, 78, 0, 136, 0, 80, 82, 110, 78, 170, 0, 138, 116, 190, 0, 264, 0, 192, 198, 204, 0, 310, 66, 294, 196, 272, 0, 398, 182, 358, 248, 328, 0, 584, 0, 372, 372, 372, 248, 658, 0, 468 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS Phi-summation over numbers not exceeding n are given in A002088, over divisor-set of n would give n, over RRS or unrelated numbers to n give newer values: at n=36 these values are {396,36,191,170}. This is a further way of Phi-summation. LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10000 EXAMPLE n=36 and its "unrelated-set" is {8,10,14,15,16,20,21,22,24,26,27,28,30,32,33,34} and their totients are {4,4,6,8,8,8,12,10,8,12,18,12,8,16,20,16}. The sum of these values is 170, so a(36)=170. For primes the unrelated set is empty and Phi-sum over empty set is 0. MAPLE A045763_row :=proc(n)     a := {} ;     dvs := numtheory[divisors](n) ;     for m from 2 to n-1 do         if igcd(m, n) >1 and not m in dvs then             a := a union {m} ;         end if;     end do:     a; end proc: A053571 := proc(n)     add(numtheory[phi](a), a=A045763_row(n)) ; end proc: # R. J. Mathar, Jan 09 2017 MATHEMATICA Table[Total@ EulerPhi@ Select[Range@ n, 1 < GCD[#, n] < # &], {n, 68}] (* Michael De Vlieger, Mar 05 2017 *) CROSSREFS Cf. A000010, A002088, A045763. Sequence in context: A284570 A256847 A046277 * A307391 A129883 A293578 Adjacent sequences:  A053568 A053569 A053570 * A053572 A053573 A053574 KEYWORD nonn AUTHOR Labos Elemer, Jan 17 2000 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.

Last modified June 2 14:21 EDT 2020. Contains 334787 sequences. (Running on oeis4.)