This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A290077 a(n) = A000010(A005940(1+n)). 9
 1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 8, 4, 20, 6, 18, 8, 10, 6, 12, 8, 24, 8, 24, 8, 42, 20, 40, 12, 100, 18, 54, 16, 12, 10, 20, 12, 40, 12, 36, 16, 60, 24, 48, 16, 120, 24, 72, 16, 110, 42, 84, 40, 168, 40, 120, 24, 294, 100, 200, 36, 500, 54, 162, 32, 16, 12, 24, 20, 48, 20, 60, 24, 72, 40, 80, 24, 200, 36, 108, 32, 120, 60, 120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Each n occurs A014197(n) times in total in this sequence. LINKS Antti Karttunen, Table of n, a(n) for n = 0..16384 FORMULA a(n) = A000010(A005940(1+n)). MATHEMATICA f[n_, i_, x_]:=f[n, i, x]=Which[n==0, x, EvenQ[n], f[n/2, i + 1, x], f[(n - 1)/2, i, x Prime[i]]]; a005940[n_]:=f[n - 1, 1, 1]; Table[EulerPhi[a005940[n + 1]], {n, 0, 100}] (* Indranil Ghosh, Jul 20 2017 *) PROG (PARI) A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ Modified from code of M. F. Hasler A290077(n) = eulerphi(A005940(1+n)); (Python/Sage) def A290077(n):     i = 1     m = 1     while n>0:       if(0==(n%2)):         n = n/2         i = i+1       else:         if(1==(n%4)):           n = (n-1)/4           m = m*(sloane.A000040(i)-1)           i = i+1         else:           n = (n-1)/2           m = m*(sloane.A000040(i))     return(m) (Scheme) (define (A290077 n) (A000010 (A005940 (+ 1 n)))) (Scheme) (define (A290077 n) (let loop ((n n) (m 1) (i 1)) (cond ((zero? n) m) ((even? n) (loop (/ n 2) m (+ 1 i))) ((= 1 (modulo n 4)) (loop (/ (- n 1) 4) (* m (- (A000040 i) 1)) (+ 1 i))) (else (loop (/ (- n 1) 2) (* m (A000040 i)) i))))) ;; Requires only an implementation of A000040, see for example under A083221. CROSSREFS Cf. A000010, A000040, A005940, A014197, A290076. Sequence in context: A086296 A096504 A277906 * A277030 A011773 A306275 Adjacent sequences:  A290074 A290075 A290076 * A290078 A290079 A290080 KEYWORD nonn AUTHOR Antti Karttunen, Jul 19 2017 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 September 16 10:36 EDT 2019. Contains 327094 sequences. (Running on oeis4.)