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A063753
Numbers k such that cototient(k) is a square and sets a new record for squares.
2
2, 6, 21, 24, 54, 96, 189, 216, 345, 384, 420, 796, 864, 1332, 1536, 1680, 2340, 3300, 3780, 5328, 6144, 6516, 6720, 8260, 8484, 9360, 10500, 13200, 14532, 15120, 18340, 19476, 20580, 24576, 26064, 26628, 26880, 29700, 33396, 33936, 34020
OFFSET
1,1
LINKS
PROG
(PARI)a=0; for(n=1, 7000, x=n-eulerphi(n); if(issquare(x), b=x; if(b>a, a=b; print(n))))
(PARI) { n=0; a=0; for (m=1, 10^9, if (issquare(b=m - eulerphi(m)), if (b>a, a=b; write("b063753.txt", n++, " ", m); if (n==275, break))) ) } \\ Harry J. Smith, Aug 29 2009
CROSSREFS
Cf. A051953.
Sequence in context: A103160 A242819 A126099 * A066893 A004192 A104143
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Aug 11 2001
EXTENSIONS
More terms from Dean Hickerson, Aug 22 2001
STATUS
approved