A079334 Numbers k such that k divides tau(k) and k+1 divides tau(k+1), where tau(k)=A000594(k) is Ramanujan's tau function; i.e., k and k+1 are in A063938.

1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 20, 24, 27, 35, 48, 49, 63, 80, 90, 91, 125, 160, 161, 224, 440, 728, 735, 2024, 2400, 2744, 4095, 4374, 12879, 13824, 20735, 30624

Offset: 1

Author

Dean Hickerson, Jan 03 2003

Keywords

• nonn
• more

Comments

No other terms < 212000. - Robert G. Wilson v, Jan 06 2002

No other terms < 30000000. - Dana Jacobsen, Sep 06 2015

Links

• Eric Weisstein's World of Mathematics, Tau Function.

Crossrefs

Cf. A000594, A063938.

Programs

Mathematica

(* First do <
				

PARI

tauvec(N) = Vec(q*eta(q + O(q^N))^24)
v=tauvec(10000); for(n=1,#v-1,if(Mod(v[n],n) == 0 && Mod(v[n+1],n+1) == 0,print1(n", "))) \\ Dana Jacobsen, Sep 06 2015

Perl

use ntheory ":all"; my @p = grep { !(ramanujan_tau($) % $) } 1..10000; for (0 .. $#p-1) { say $p[$] if $p[$]+1 == $p[$+1] } # _Dana Jacobsen, Sep 06 2015