A079393 Numbers for which Ramanujan's tau function is negative.

2, 4, 6, 7, 9, 10, 12, 13, 17, 20, 21, 22, 25, 27, 30, 31, 32, 35, 37, 38, 39, 43, 44, 45, 46, 49, 51, 53, 56, 58, 59, 60, 65, 66, 67, 72, 75, 76, 77, 82, 83, 85, 89, 92, 93, 94, 96, 99, 103, 104, 105, 110, 111, 112, 113, 114, 116, 122, 125, 126, 127, 129

Offset

0,1

Links

G. C. Greubel, Table of n, a(n) for n = 0..10000

Example

A000594(2) = -24, so a(1) = 2.

Mathematica

Select[Range[200], RamanujanTau[#] < 0 &] (* Carl Najafi, Sep 09 2011 *)

Prog

(PARI) T(n)=n*(n+1)/2 rtau3(n)=local(y, j); y=0; j=1; while (T(j-1)<n, j++); j--; for (i=1, j, y=y-(-1)^i*(2*i-1)*x^(T(i-1))); y=y^8; polcoeff(y, n-1) for (n=1, 100, if (rtau3(n)<0, print1(n", ")))
(PARI) isok(n) = ramanujantau(n) < 0; \\ Michel Marcus, Jan 20 2019

Crossrefs

Cf. A079392, A000594.

Sequence in context: A248612 A247000 A213356 * A047512 A026273 A184658

Adjacent sequences: A079390 A079391 A079392 * A079394 A079395 A079396

Keyword

nonn

Author

Jon Perry, Jan 06 2003

Status

approved