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A014905
a(1)=1, a(n) = 21*a(n-1) + n.
2
1, 23, 486, 10210, 214415, 4502721, 94557148, 1985700116, 41699702445, 875693751355, 18389568778466, 386180944347798, 8109799831303771, 170305796457379205, 3576421725604963320, 75104856237704229736
OFFSET
1,2
FORMULA
a(1)=1, a(2)=23, a(3)=486, a(n) = 23*a(n-1) - 43*a(n-2) + 21*a(n-3). - Vincenzo Librandi, Oct 19 2012
MATHEMATICA
LinearRecurrence[{23, -43, 21}, {1, 23, 486}, 20] (* Vincenzo Librandi, Oct 19 2012 *)
PROG
(Magma) I:=[1, 23, 486]; [n le 3 select I[n] else 23*Self(n-1) - 43*Self(n-2)+ 21*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Oct 19 2012
CROSSREFS
Sequence in context: A273008 A015678 A293083 * A200734 A218715 A133283
KEYWORD
nonn
STATUS
approved