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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
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]:= 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: A069553 A275826 A371238 * A093968 A064713 A162213
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