Search: id:A003557 Results 1-1 of 1 results found. %I A003557 %S A003557 1,1,1,2,1,1,1,4,3,1,1,2,1,1,1,8,1,3,1,2,1,1,1,4,5,1,9,2,1,1,1,16,1, %T A003557 1,1,6,1,1,1,4,1,1,1,2,3,1,1,8,7,5,1,2,1,9,1,4,1,1,1,2,1,1,3,32,1,1, %U A003557 1,2,1,1,1,12,1,1,5,2,1,1,1,8,27,1,1,2,1,1,1,4,1,3,1,2,1,1,1,16,1,7 %N A003557 n divided by largest square-free divisor of n. %C A003557 a(n) is the size of the Frattini subgroup of the cyclic group C_n - Ahmed Fares (ahmedfares(AT)my-deja.com), Jun 07 2001. Also of the Frattini subgroup of the dihedral group with 2*n elements. - Sharon Sela (sharonsela(AT)hotmail.com), Jan 01 2002 %C A003557 Number of solutions to x^m==0 (mod n) provided that n < 2^(m+1), i.e. the sequence of sequences A000188, A000189, A000190, etc. converges to this sequence. - Henry Bottomley (se16(AT)btinternet.com), Sep 18 2001 %C A003557 a(n) is the number of nilpotent elements in the ring Z/nZ. - Laszlo Toth (ltoth(AT)ttk.pte.hu), May 22 2009 %C A003557 The sequence of partial products of a(n) is A085056(n). [From Peter Luschny (peter(AT)luschny.de), Jun 29 2009] %H A003557 R. Zumkeller, Table of n, a(n) for n = 1..10000 %H A003557 H. Bottomley, Some Smarandache-type multiplicative sequences %H A003557 S. R. Finch, Idempotents and Nilpotents Modulo n (arXiv:math.NT/0605019) %F A003557 Multiplicative with a(p^e) = p^(e-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 23 2001 %p A003557 Contribution from Peter Luschny (peter(AT)luschny.de), Jun 29 2009: (Start) %p A003557 A003557 := proc(n) local A, p, i, j, h, q; %p A003557 A := [seq(j,j=1..n)]; p := 2; %p A003557 while p <= n do for j from p by p to n do %p A003557 if irem(A[j], p, 'q') = 0 then A[j] := q fi od; %p A003557 p := nextprime(p) od; A end: %p A003557 (End) %t A003557 Prepend[ Array[ #/Times@@(First[ Transpose[ FactorInteger[ # ] ] ])&, 100, 2 ], 1 ] %Y A003557 Cf. A007947, A062378, A062379. %Y A003557 Sequence in context: A104445 A000189 A000190 this_sequence A073752 A128708 A087653 %Y A003557 Adjacent sequences: A003554 A003555 A003556 this_sequence A003558 A003559 A003560 %K A003557 nonn,easy,mult %O A003557 1,4 %A A003557 Marc LeBrun (mlb(AT)well.com) %E A003557 Program added Apr 10, 1997 (og). Search completed in 0.002 seconds