A163070
a(n) = ((4+sqrt(5))*(2+sqrt(5))^n + (4-sqrt(5))*(2-sqrt(5))^n)/2.
Original entry on oeis.org
4, 13, 56, 237, 1004, 4253, 18016, 76317, 323284, 1369453, 5801096, 24573837, 104096444, 440959613, 1867934896, 7912699197, 33518731684, 141987625933, 601469235416, 2547864567597, 10792927505804, 45719574590813
Offset: 0
Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009
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Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((4+r)*(2+r)^n+(4-r)*(2-r)^n)/2: n in [0..21] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 21 2009
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LinearRecurrence[{4,1},{4,13},30] (* Harvey P. Dale, Sep 19 2011 *)
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x='x+O('x^30); Vec((4-3*x)/(1-4*x-x^2)) \\ G. C. Greubel, Jan 08 2018
A163069
a(n) = ((4+sqrt(5))*(1+sqrt(5))^n + (4-sqrt(5))*(1-sqrt(5))^n)/2.
Original entry on oeis.org
4, 9, 34, 104, 344, 1104, 3584, 11584, 37504, 121344, 392704, 1270784, 4112384, 13307904, 43065344, 139362304, 450985984, 1459421184, 4722786304, 15283257344, 49457659904, 160048349184, 517927337984, 1676048072704
Offset: 0
Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009
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Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((4+r)*(1+r)^n+(4-r)*(1-r)^n)/2: n in [0..23] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 21 2009
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LinearRecurrence[{2, 4}, {4, 9}, 30] (* G. C. Greubel, Jan 08 2018 *)
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x='x+O('x^30); Vec((4+x)/(1-2*x-4*x^2)) \\ G. C. Greubel, Jan 08 2018
A163071
a(n) = ((4+sqrt(5))*(3+sqrt(5))^n + (4-sqrt(5))*(3-sqrt(5))^n)/2.
Original entry on oeis.org
4, 17, 86, 448, 2344, 12272, 64256, 336448, 1761664, 9224192, 48298496, 252894208, 1324171264, 6933450752, 36304019456, 190090313728, 995325804544, 5211593572352, 27288258215936, 142883175006208, 748146017173504
Offset: 0
Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009
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Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((4+r)*(3+r)^n+(4-r)*(3-r)^n)/2: n in [0..20] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 21 2009
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LinearRecurrence[{6,-4},{4,17},40] (* Harvey P. Dale, Feb 12 2013 *)
A163072
a(n) = ((4+sqrt(5))*(5+sqrt(5))^n + (4-sqrt(5))*(5-sqrt(5))^n)/2.
Original entry on oeis.org
4, 25, 170, 1200, 8600, 62000, 448000, 3240000, 23440000, 169600000, 1227200000, 8880000000, 64256000000, 464960000000, 3364480000000, 24345600000000, 176166400000000, 1274752000000000, 9224192000000000, 66746880000000000
Offset: 0
Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009
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Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((4+r)*(5+r)^n+(4-r)*(5-r)^n)/2: n in [0..19] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 21 2009
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LinearRecurrence[{10, -20}, {4, 25}, 30] (* G. C. Greubel, Jan 08 2018 *)
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x='x+O('x^30); Vec((4-15*x)/(1-10*x+20*x^2)) \\ G. C. Greubel, Jan 08 2018
Showing 1-4 of 4 results.
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