A063753 Numbers k such that cototient(k) is a square and sets a new record for squares.

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

Harry J. Smith, Table of n, a(n) for n = 1..275

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

Adjacent sequences: A063750 A063751 A063752 * A063754 A063755 A063756

Keyword

easy,nonn

Author

Jason Earls, Aug 11 2001

Extensions

More terms from Dean Hickerson, Aug 22 2001

Status

approved