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A074513
a(n) = 1^n + 4^n + 7^n.
0
3, 12, 66, 408, 2658, 17832, 121746, 839928, 5830338, 40615752, 283523826, 1981521048, 13858064418, 96956119272, 678491508306, 4748635251768, 33237225536898, 232647693856392, 1628482317387186, 11399170063280088
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-x) + 1/(1-4*x) + 1/(1-7*x).
E.g.f.: e^x + e^(4*x) + e^(7*x). (End)
a(n) = 11*a(n-1) - 28*a(n-2) + 18 with a(0)=3, a(1)=12. - Vincenzo Librandi, Jul 21 2010
a(0)=3, a(1)=12, a(2)=66, a(n) = 12*a(n-1) - 39*a(n-2) + 28*a(n-3). - Harvey P. Dale, Mar 06 2013
MATHEMATICA
Table[1^n + 4^n + 7^n, {n, 0, 20}]
LinearRecurrence[{12, -39, 28}, {3, 12, 66}, 30] (* Harvey P. Dale, Mar 06 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved