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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.
1
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
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
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