A063940 - OEIS

A063940

Composite numbers k such that Ramanujan's function tau(k) (A000594) is not divisible by k.

22, 26, 33, 34, 38, 39, 44, 46, 51, 52, 55, 57, 58, 62, 65, 66, 68, 69, 74, 76, 77, 78, 82, 85, 86, 87, 93, 94, 95, 99, 102, 104, 106, 110, 111, 114, 116, 117, 118, 119, 121, 122, 123, 124, 129, 130, 132, 133, 134, 136, 138, 141, 142, 143, 145, 146, 148, 152, 153

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

22 is a term because Ramanujan's tau(22) = 18643272 and 18643272 mod 22 = 10.

MATHEMATICA

Select[ Range[ 70 ], Mod[ CoefficientList[ Take[ Expand[ Product[ (1 - x^k)^24, {k, 1, 70} ] ], 70 ], x ][ [ # ] ], # ] != 0 && ! PrimeQ[ # ] & ]

(* First do *) <<NumberTheory`Ramanujan` (* then *) Select[ Range[ 153], Mod[ RamanujanTau[ # ], # ] != 0 && ! PrimeQ[ # ] &] (* Dean Hickerson, Jan 03 2003 *)

CROSSREFS

Cf. A000594, A063938, A007659.

Sequence in context: A066059 A084891 A162422 * A046442 A101549 A277624

Adjacent sequences: A063937 A063938 A063939 * A063941 A063942 A063943

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Aug 31 2001

STATUS

approved