A178420
Partial sums of floor(2^n/3).
Original entry on oeis.org
0, 1, 3, 8, 18, 39, 81, 166, 336, 677, 1359, 2724, 5454, 10915, 21837, 43682, 87372, 174753, 349515, 699040, 1398090, 2796191, 5592393, 11184798, 22369608, 44739229, 89478471, 178956956, 357913926, 715827867, 1431655749, 2863311514
Offset: 1
a(5) = 0 + 1 + 2 + 5 + 10 = 18.
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[Floor((4*2^n-3*n-4)/6): n in [1..30]]; // Vincenzo Librandi, Jun 23 2011
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seq(round((4*2^n-3*n-4)/6),n=1..50)
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f[n_] := Floor[(4 2^n - 3 n - 4)/6]; f[Range[60]] (* Vladimir Joseph Stephan Orlovsky, Jan 29 2011 *)
CoefficientList[Series[x / ((1 + x) (1 - 2 x) (1 - x)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Mar 26 2014 *)
LinearRecurrence[{3,-1,-3,2},{0,1,3,8},40] (* or *) Accumulate[ Table[ Floor[ 2^n/3],{n,40}]] (* Harvey P. Dale, Dec 24 2015 *)
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a(n)=(4<Charles R Greathouse IV, Jul 31 2013
A368343
Square array T(n,k), n >= 3, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{j=0..n} k^(n-j) * floor(j/3).
Original entry on oeis.org
1, 1, 1, 1, 2, 1, 1, 3, 3, 2, 1, 4, 7, 5, 2, 1, 5, 13, 16, 7, 2, 1, 6, 21, 41, 34, 9, 3, 1, 7, 31, 86, 125, 70, 12, 3, 1, 8, 43, 157, 346, 377, 143, 15, 3, 1, 9, 57, 260, 787, 1386, 1134, 289, 18, 4, 1, 10, 73, 401, 1562, 3937, 5547, 3405, 581, 22, 4
Offset: 3
Square array begins:
1, 1, 1, 1, 1, 1, 1, ...
1, 2, 3, 4, 5, 6, 7, ...
1, 3, 7, 13, 21, 31, 43, ...
2, 5, 16, 41, 86, 157, 260, ...
2, 7, 34, 125, 346, 787, 1562, ...
2, 9, 70, 377, 1386, 3937, 9374, ...
3, 12, 143, 1134, 5547, 19688, 56247, ...
A097137
Convolution of 3^n and floor(n/2).
Original entry on oeis.org
0, 0, 1, 4, 14, 44, 135, 408, 1228, 3688, 11069, 33212, 99642, 298932, 896803, 2690416, 8071256, 24213776, 72641337, 217924020, 653772070, 1961316220, 5883948671, 17651846024, 52955538084, 158866614264, 476599842805
Offset: 0
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a:=[0,0,1,4];; for n in [5..30] do a[n]:=4*a[n-1]-2*a[n-2]-4*a[n-3] +3*a[n-4]; od; a; # G. C. Greubel, Jul 14 2019
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[Round((3*3^n-4*n-4)/16): n in [0..30]]; // Vincenzo Librandi, Jun 25 2011
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A097137 := proc(n) add( floor(3^i/8),i=0..n) ; end proc:
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CoefficientList[Series[x^2/((1-x)^2(1-3x)(1+x)),{x,0,30}],x] (* Harvey P. Dale, Mar 11 2011 *)
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my(x='x+O('x^30)); concat([0,0], Vec(x^2/((1-x)^2*(1-3*x)*(1+x)))) \\ G. C. Greubel, Jul 14 2019
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(x^2/((1-x)^2*(1-3*x)*(1+x))).series(x, 30).coefficients(x, sparse=False) # G. C. Greubel, Jul 14 2019
A097138
Convolution of 4^n and floor(n/2).
Original entry on oeis.org
0, 0, 1, 5, 22, 90, 363, 1455, 5824, 23300, 93205, 372825, 1491306, 5965230, 23860927, 95443715, 381774868, 1527099480, 6108397929, 24433591725, 97734366910, 390937467650, 1563749870611, 6254999482455, 25019997929832
Offset: 0
a(3) = 1/3*floor(4^0/5)+1/3*floor(4^1/5)+1/3*floor(4^2/5) +1/3*floor(4^3/5) = 0 + 0 + 1 + 4 = 5.
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[(4^(n+2)-30*n+9*(-1)^n-25)/180: n in [0..30]]; // Vincenzo Librandi, May 31 2011
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A097138 := proc(n) (4^(n+2)-30*n+9*(-1)^n-25)/180 ; end proc: # R. J. Mathar, Jan 08 2011
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LinearRecurrence[{5,-3,-5,4},{0,0,1,5},30] (* Harvey P. Dale, Sep 17 2017 *)
A097139
Convolution of 5^n and floor(n/2).
Original entry on oeis.org
0, 0, 1, 6, 32, 162, 813, 4068, 20344, 101724, 508625, 2543130, 12715656, 63578286, 317891437, 1589457192, 7947285968, 39736429848, 198682149249, 993410746254, 4967053731280, 24835268656410, 124176343282061, 620881716410316
Offset: 0
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[5^(n+1)/96 -n/8 -3/32 +(-1)^n/24: n in [0..30]]; // Vincenzo Librandi, Jun 25 2011
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A097139 := proc(n) 5^(n+1)/96 -n/8 -3/32 +(-1)^n/24 ; end proc: # R. J. Mathar, Jan 08 2011
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f[n_] := Floor[5^n/6]/4; Accumulate@ Array[f, 24, 0]
a[n_] := a[n] = 6 a[n - 1] - 4 a[n - 2] - 6 a[n - 3] + 5 a[n - 4]; a[0] = a[1] = 0; a[2] = 1; a[3] = 6; Array[a, 24, 0]
CoefficientList[ Series[x^2/((1 - x) (1 - 5 x) (1 - x^2)), {x, 0, 23}], x] (* Robert G. Wilson v, Jan 02 2011 *)
LinearRecurrence[{6,-4,-6,5},{0,0,1,6},30] (* Harvey P. Dale, Mar 16 2019 *)
A178719
Partial sums of (1/5)*floor(6^n/7).
Original entry on oeis.org
0, 0, 1, 7, 44, 266, 1599, 9597, 57586, 345520, 2073125, 12438755, 74632536, 447795222, 2686771339, 16120628041, 96723768254, 580342609532, 3482055657201, 20892333943215, 125354003659300, 752124021955810, 4512744131734871, 27076464790409237, 162458788742455434, 974752732454732616
Offset: 0
a(3) = (1/5)*(floor(6^1/7) + floor(6^2/7) + floor(6^3/7)) = (1/5)*(0+5+30) = (1/5)*35 = 7.
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[(1/5)*Floor((12*6^n-35*n-12)/70): n in [0..30]]; // Vincenzo Librandi, Jun 21 2011
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A178719 := proc(n) add( floor(6^i/7)/5,i=0..n) ; end proc:
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f[n_] := Floor[6^n/7]/5; Accumulate@ Array[f, 22]
CoefficientList[Series[x^2/((1+x)(1-6x)(1-x)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Mar 26 2014 *)
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vector(30, n, n--; (((12*6^n-35*n-12)/70)\1)/5) \\ G. C. Greubel, Jan 24 2019
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[floor((12*6^n-35*n-12)/70)/5 for n in (0..30)] # G. C. Greubel, Jan 24 2019
A178730
Partial sums of floor(7^n/8)/6.
Original entry on oeis.org
0, 1, 8, 58, 408, 2859, 20016, 140116, 980816, 6865717, 48060024, 336420174, 2354941224, 16484588575, 115392120032, 807744840232, 5654213881632, 39579497171433, 277056480200040, 1939395361400290, 13575767529802040, 95030372708614291, 665212608960300048, 4656488262722100348, 32595417839054702448
Offset: 1
a(3) = (1/6)*(floor(7/8) + floor(7^2/8) + floor(7^3/8)) = (1/6)*(0+6+42) = 8.
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[Floor((7*7^n-24*n-7)/48)/6: n in [1..30]]; // Vincenzo Librandi, Jun 21 2011
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A178730 := proc(n) add( floor(7^i/8)/6,i=0..n) ; end proc:
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CoefficientList[Series[x/((1+x)(1-7x)(1-x)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Mar 26 2014 *)
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vector(30, n, (((7^(n+1)-24*n-7)/48)\1)/6) \\ G. C. Greubel, Jan 24 2019
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[floor((7^(n+1)-24*n-7)/48)/6 for n in (1..30)] # G. C. Greubel, Jan 24 2019
A178827
Partial sums of floor(8^n/9)/7.
Original entry on oeis.org
0, 1, 9, 74, 594, 4755, 38043, 304348, 2434788, 19478309, 155826477, 1246611822, 9972894582, 79783156663, 638265253311, 5106122026496, 40848976211976, 326791809695817, 2614334477566545, 20914675820532370, 167317406564258970, 1338539252514071771, 10708314020112574179, 85666512160900593444, 685332097287204747564
Offset: 1
a(3) = (1/7)*(floor(8/9) + floor(64/9) + floor(512/9)) = (1/7)*(0 + 7 + 56) = (1/7)*63 = 9.
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a:=[0,1,9,74];; for n in [5..30] do a[n]:=9*a[n-1]-7*a[n-2]-9*a[n-3] +8*a[n-4]; od; a; # G. C. Greubel, Jan 22 2019
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[ &+[Floor(8^k/9)/7: k in [1..n]]: n in [1..25] ]; // Bruno Berselli, Apr 28 2011
(Decimal BASIC)
FOR n=1 TO 1000
PRINT n; (32*8^n-126*n-81+49*(-1)^n)/1764
NEXT n
END ! Bruno Berselli, Apr 28 2011
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A178827 := proc(n) add( floor(8^i/9)/7,i=0..n) ; end proc:
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Rest[CoefficientList[Series[x^2/((1+x)*(1-8*x)*(1-x)^2), {x,0,30}],x]] (* G. C. Greubel, Jan 22 2019 *)
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my(x='x+O('x^30)); concat([0], Vec(x^2/((1+x)*(1-8*x)*(1-x)^2))) \\ G. C. Greubel, Jan 22 2019
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a=(x^2/((1+x)*(1-8*x)*(1-x)^2)).series(x, 30).coefficients(x, sparse=False); a[1:] # G. C. Greubel, Jan 22 2019
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