A076507 Three people (P1, P2, P3) are in a circle and are saying Hello to each other. They start with P2 saying "Hello, Hello". Thereafter Pn says "Hello" for n times the total number of Hello's so far.

2, 6, 8, 32, 144, 192, 768, 3456, 4608, 18432, 82944, 110592, 442368, 1990656, 2654208, 10616832, 47775744, 63700992, 254803968, 1146617856, 1528823808, 6115295232, 27518828544, 36691771392, 146767085568, 660451885056

Offset

1,1

Links

Table of n, a(n) for n=1..26.

Index entries for linear recurrences with constant coefficients, signature (0,0,24).

Formula

G.f.: 2*x*(1-x)*(1+4*x+8*x^2)/(1-24*x^3). [Colin Barker, Jun 07 2012]

Mathematica

LinearRecurrence[{0, 0, 24}, {2, 6, 8, 32}, 30] (* Harvey P. Dale, Sep 10 2021 *)

Prog

(PARI) mod 3(n)=if (i%3==0, 3, i%3) s=2; for (i=3, 30, print1(s*mod 3(i), ", "); s=s+s*mod 3(i))

Crossrefs

Cf. A076508.

Sequence in context: A096999 A019199 A094678 * A117542 A045653 A235320

Adjacent sequences: A076504 A076505 A076506 * A076508 A076509 A076510

Keyword

nonn,easy

Author

Jon Perry, Oct 15 2002

Extensions

a(16) corrected by Colin Barker, Jun 07 2012

Better definition and corrected value for a(24) from Sean A. Irvine, May 19 2019

Status

approved