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A014916
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a(1)=1, a(n)=n*4^(n-1)+a(n-1).
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5
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1, 9, 57, 313, 1593, 7737, 36409, 167481, 757305, 3378745, 14913081, 65244729, 283348537, 1222872633, 5249404473, 22429273657, 95443717689, 404681363001, 1710351420985, 7207909559865, 30297653743161, 127054676987449
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a(n)=(1/9)*[1+4^n*(3*n-1)], with n>=1 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jan 13 2009]
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MAPLE
| a:=n->sum (4^n-4^j, j=0..n): seq(a(n)/3, n=1..31); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 14 2008]
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MATHEMATICA
| Join[{a=1, b=9}, Table[c=8*b-16*a+1; a=b; b=c, {n, 60}]] (*From Vladimir Joseph Stephan Orlovsky, Feb 07 2011*)
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CROSSREFS
| Sequence in context: A027210 A192054 A045720 * A045635 A026896 A080961
Adjacent sequences: A014913 A014914 A014915 * A014917 A014918 A014919
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KEYWORD
| nonn,easy
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AUTHOR
| Olivier Gerard (olivier.gerard(AT)gmail.com)
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