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A076505 3 people at a party are saying Hello to each other. Person 1 says Hello. Person 2 counts the times Hello has been said and says Hello twice that number. Person 3 says Hello 3 times the sum of Hello's and then it is Person 1 again. This is how many Hello's each person says. 1
1, 2, 9, 12, 48, 216, 288, 1152, 5184, 6912, 27648, 124416, 165888, 663552, 2985984, 3981312, 15925248, 71663616, 95551488, 382205952, 1719926784, 2293235712, 9172942848, 41278242816, 55037657088, 220150628352, 990677827584 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

FORMULA

For n>4, a(n) = a(n-3)*4!. - Rob Hoogers (chimera(AT)chimera.fol.nl), Jun 27 2004.

a(n) = 2^i*3^j, with i=A064429(n-1), j=[n/3]+[n%3==0].

PROG

(PARI) mod 3(n)=if (i%3==0, 3, i%3) s=1; for (i=2, 30, print1(s*mod 3(i), ", "); s=s+s*mod 3(i))

CROSSREFS

Cf. A076506.

Sequence in context: A178312 A126977 A102237 * A129345 A125019 A024976

Adjacent sequences:  A076502 A076503 A076504 * A076506 A076507 A076508

KEYWORD

nonn

AUTHOR

Jon Perry (perry(AT)globalnet.co.uk), Oct 15 2002

EXTENSIONS

More terms from Rob Hoogers (chimera(AT)chimera.fol.nl), Jun 27 2004

An incorrect comment was deleted, Aug 02 2010

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Last modified February 16 13:12 EST 2012. Contains 205909 sequences.