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!)
 A143481 a(n) = phi(A143480(n)) where phi(m) = A000010(m). 4
 1, 2, 6, 8, 20, 24, 42, 48, 54, 64, 110, 112, 120, 132, 144, 160, 192, 216, 288, 320, 324, 360, 396, 416, 440, 480, 486, 504, 616, 624, 660, 672, 720, 736, 840, 864, 1008, 1044, 1104, 1120, 1200, 1224, 1260, 1280, 1296, 1320, 1380, 1408, 1512, 1560, 1632, 1680 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Previous name was: a(n) is the number of positive integers <= A143480(n) and coprime to A143480(n). a(n+1) > a(n) for all n. LINKS Ivan Neretin and Peter Kagey, Table of n, a(n) for n = 1..10000, first 1000 terms from Ivan Neretin FORMULA a(n) = phi(A143480(n)) = A000010(A143480(n)). MAPLE A:= 1: for n from 2 to 100 do   for k from n by n do      r:= numtheory:-phi(k);      if r > A[n-1] then         A[n]:= r;         break      fi   od: od: seq(A[i], i=1..100); # Robert Israel, Sep 04 2015 MATHEMATICA a = b = {1}; Do[k = 1; While[(r = EulerPhi[nxt = k*n]) <= b[[-1]], k++]; AppendTo[a, nxt]; AppendTo[b, r], {n, 2, 52}]; b (* Ivan Neretin, May 25 2015 *) CROSSREFS Cf. A143480. A143483 is an analogous sequence with A143482 as the referenced sequence. Sequence in context: A135616 A069553 A275826 * A093968 A064713 A162213 Adjacent sequences:  A143478 A143479 A143480 * A143482 A143483 A143484 KEYWORD nonn AUTHOR Leroy Quet, Aug 19 2008 EXTENSIONS Extended by Ray Chandler, Nov 09 2008 Name changed by Peter Kagey, Sep 03 2015 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 August 12 11:42 EDT 2020. Contains 336439 sequences. (Running on oeis4.)