A016129
Expansion of 1/((1-2*x)*(1-6*x)).
Original entry on oeis.org
1, 8, 52, 320, 1936, 11648, 69952, 419840, 2519296, 15116288, 90698752, 544194560, 3265171456, 19591036928, 117546237952, 705277460480, 4231664828416, 25389989101568, 152339934871552, 914039609753600, 5484237659570176, 32905425959518208, 197432555761303552
Offset: 0
Sequences with gf 1/((1-n*x)*(1-6*x)):
A000400 (n=0),
A003464 (n=1), this sequence (n=2),
A016137 (n=3),
A016149 (n=4),
A005062 (n=5),
A053469 (n=6),
A016169 (n=7),
A016170 (n=8),
A016172 (n=9),
A016173 (n=10),
A016174 (n=11),
A016175 (n=12).
-
[(6^(n+1)-2^(n+1))/4 : n in [0..30]]; // Vincenzo Librandi, Oct 09 2011
-
Table[(6^(n+1) -2^(n+1))/4, {n,0,40}] (* Vladimir Joseph Stephan Orlovsky, Jan 19 2011 *)
CoefficientList[Series[1/((1-2x)(1-6x)),{x,0,30}],x] (* or *) LinearRecurrence[{8,-12},{1,8},30] (* Harvey P. Dale, Jan 15 2015 *)
-
Vec(1/(1-2*x)/(1-6*x)+O(x^30)) \\ Charles R Greathouse IV, Apr 17 2012
-
[lucas_number1(n,8,12) for n in range(1, 31)] # Zerinvary Lajos, Apr 23 2009
-
[(6^n - 2^n)/4 for n in range(1,31)] # Zerinvary Lajos, Jun 04 2009
A053541
a(n) = n*10^(n-1).
Original entry on oeis.org
1, 20, 300, 4000, 50000, 600000, 7000000, 80000000, 900000000, 10000000000, 110000000000, 1200000000000, 13000000000000, 140000000000000, 1500000000000000, 16000000000000000, 170000000000000000
Offset: 1
- Albert H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
-
List([1..20], n-> n*10^(n-1)) # G. C. Greubel, May 16 2019
-
[n*10^(n-1): n in [1..30]]; // Vincenzo Librandi, Jun 06 2011
-
seq(n*10^(n-1), n = 1 .. 40); # Bernard Schott, Nov 17 2022
-
f[n_]:=n*10^(n-1);f[Range[40]] (* Vladimir Joseph Stephan Orlovsky, Feb 09 2011*)
LinearRecurrence[{20,-100},{1,20},20] (* Harvey P. Dale, Aug 08 2023 *)
-
a(n)=n*10^(n-1) \\ Charles R Greathouse IV, Dec 05 2011
-
[n*10^(n-1) for n in (1..20)] # G. C. Greubel, May 16 2019
A212700
a(n) = 5*n*6^(n-1).
Original entry on oeis.org
5, 60, 540, 4320, 32400, 233280, 1632960, 11197440, 75582720, 503884800, 3325639680, 21767823360, 141490851840, 914248581120, 5877312307200, 37614798766080, 239794342133760, 1523399350026240, 9648195883499520, 60935974001049600, 383896636206612480, 2413064570441564160
Offset: 1
Cf.
A001787,
A212697,
A212698,
A212699,
A212701,
A212702,
A212703,
A212704 (b = 2, 3, 4, 5, 7, 8, 9, 10).
-
Rest@ CoefficientList[Series[5 x/(6 x - 1)^2, {x, 0, 18}], x] (* or *)
Array[5 # 6^(# - 1) &, 18] (* Michael De Vlieger, Nov 18 2019 *)
-
mtrans(n, b) = n*(b-1)*b^(n-1);
for (n=1, 100, write("b212700.txt", n, " ", mtrans(n, 6)))
Original entry on oeis.org
1, 14, 147, 1372, 12005, 100842, 823543, 6588344, 51883209, 403536070, 3107227739, 23727920916, 179936733613, 1356446145698, 10173346092735, 75960984159088, 564959819683217, 4187349251769726, 30939858360298531, 227977903707462860, 1675637592249852021, 12288009009832248154
Offset: 1
- A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
-
[n*7^(n-1): n in [1..35]]; // Vincenzo Librandi, Jun 06 2011
-
Join[{a=1,b=14},Table[c=14*b-49*a;a=b;b=c,{n,60}]] (* Vladimir Joseph Stephan Orlovsky, Feb 01 2011 *)
LinearRecurrence[{14,-49},{1, 14},19] (* Stefano Spezia, May 05 2024 *)
More terms from Larry Reeves (larryr(AT)acm.org), May 29 2001
A053540
a(n) = n*9^(n-1).
Original entry on oeis.org
1, 18, 243, 2916, 32805, 354294, 3720087, 38263752, 387420489, 3874204890, 38354628411, 376572715308, 3671583974253, 35586121596606, 343151886824415, 3294258113514384, 31501343210481297, 300189270593998242, 2851798070642983299, 27017034353459841780
Offset: 1
More terms from Larry Reeves (larryr(AT)acm.org), May 29 2001
A053539
a(n) = n * 8^(n-1).
Original entry on oeis.org
0, 1, 16, 192, 2048, 20480, 196608, 1835008, 16777216, 150994944, 1342177280, 11811160064, 103079215104, 893353197568, 7696581394432, 65970697666560, 562949953421312, 4785074604081152, 40532396646334464, 342273571680157696, 2882303761517117440, 24211351596743786496
Offset: 0
- Albert H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- A. R. Ashrafi, B. Manoochehrian, and H. Yousefi-Azari, On Szeged polynomial of a graph, Bull. Iranian Math. Soc., 33, 2007, 37-46. - _Emeric Deutsch_, Aug 06 2014
- Zbigniew R. Bogdanowicz, The number of spanning trees in a superprism, Discrete Math. Lett. 13 (2024) 66-73. See Theorem 3.1.
- Frank Ellermann, Illustration of binomial transforms.
- Index entries for linear recurrences with constant coefficients, signature (16,-64).
-
List([0..20], n-> n*8^(n-1)); # G. C. Greubel, May 16 2019
-
[n*8^(n-1): n in [0..20]]; // Vincenzo Librandi, Feb 09 2011
-
a := proc(n) option remember; if n<2 then n else 16*a(n-1)-64*a(n-2) end if end proc: seq(a(n), n = 0 .. 20); # Emeric Deutsch, Aug 06 2014
-
Table[n 8^(n-1),{n,0,20}] (* or *) LinearRecurrence[{16,-64},{0,1},20] (* Harvey P. Dale, Feb 01 2017 *)
-
a(n) = n*8^(n-1); \\ Joerg Arndt, Aug 07 2014
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[n*8^(n-1) for n in (0..20)] # G. C. Greubel, May 16 2019
A027271
a(n) = Sum_{k=0..2n} (k+1)*T(n,k), where T is given by A026536.
Original entry on oeis.org
1, 4, 18, 48, 180, 432, 1512, 3456, 11664, 25920, 85536, 186624, 606528, 1306368, 4199040, 8957952, 28553472, 60466176, 191476224, 403107840, 1269789696, 2660511744, 8344332288, 17414258688, 54419558400, 113192681472, 352638738432, 731398864896, 2272560758784
Offset: 0
-
[Round(6^(n/2)*( 3*((n+1) mod 2) + Sqrt(6)*(n mod 2) )*(n+1)/3): n in [0..40]]; // G. C. Greubel, Apr 12 2022
-
T[n_, k_]:= T[n, k]= If[k==0 || k==2*n, 1, If[k==1 || k==2*n-1, Floor[n/2], If[EvenQ[n], T[n-1, k-2] +T[n-1, k-1] +T[n-1, k], T[n-1, k-2] +T[n-1, k]] ]];
A027271[n_]:= A027271[n]= Sum[(k+1)*T[n,k], {k,0,2*n}];
Table[A027271[n], {n,0,40}] (* G. C. Greubel, Apr 12 2022 *)
-
A027271(n)=my(b(n)=if(!bittest(n,0),n\2*6^(n\2-1)));4*b(n+1)+b(n+2)+6*b(n) \\ could be made more efficient and explicit by simplifying the formula for n even and for n odd separately. - M. F. Hasler, Sep 29 2012
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[6^(n/2)*( 3*((n+1)%2) + sqrt(6)*(n%2) )*(n+1)/3 for n in (0..40)] # G. C. Greubel, Apr 12 2022
A104002
Triangle T(n,k) read by rows: number of permutations in S_n avoiding all k-length patterns that start with 1 except one fixed pattern and containing it exactly once.
Original entry on oeis.org
1, 2, 1, 3, 4, 1, 4, 12, 6, 1, 5, 32, 27, 8, 1, 6, 80, 108, 48, 10, 1, 7, 192, 405, 256, 75, 12, 1, 8, 448, 1458, 1280, 500, 108, 14, 1, 9, 1024, 5103, 6144, 3125, 864, 147, 16, 1, 10, 2304, 17496, 28672, 18750, 6480, 1372, 192, 18, 1, 11, 5120, 59049, 131072
Offset: 2
Triangle begins:
1;
2, 1;
3, 4, 1;
4, 12, 6, 1;
5, 32, 27, 8, 1;
6, 80, 108, 48, 10, 1;
7, 192, 405, 256, 75, 12, 1;
8, 448, 1458, 1280, 500, 108, 14, 1;
- Michael De Vlieger, Table of n, a(n) for n = 2..11176 (rows 2 <= n <= 150).
- T. Mansour, Permutations containing and avoiding certain patterns, arXiv:math/9911243 [math.CO], 1999-2000.
- Boris Putievskiy, Transformations Integer Sequences And Pairing Functions, arXiv:1212.2732 [math.CO], 2012.
- Franck Ramaharo, A generating polynomial for the pretzel knot, arXiv:1805.10680 [math.CO], 2018.
Cf. Left-edge columns include
A001787,
A027471,
A002697,
A053464,
A053469,
A027473,
A053539,
A053540,
A053541,
A081127,
A081128.
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Table[(n - k + 1) (k - 1)^(n - k), {n, 2, 12}, {k, 2, n}] // Flatten (* Michael De Vlieger, Aug 22 2018 *)
A121124
Unbranched a-4-catapolynonagons (see Brunvoll reference for precise definition).
Original entry on oeis.org
1, 4, 21, 138, 864, 5526, 34992, 221724, 1399680, 8818632, 55427328, 347684400, 2176782336, 13604912928, 84894511104, 528958247616, 3291294892032, 20453047668864, 126949945835520, 787089669219072, 4874877920083968, 30163307160752640, 186464080443211776, 1151689908801235968
Offset: 2
- J. Brunvoll, S. J. Cyvin and B. N. Cyvin, Isomer enumeration of polygonal systems..., J. Molec. Struct. (Theochem), 364 (1996), 1-13, Table 12, q=9, alpha=1.
- Index entries for linear recurrences with constant coefficients, signature (12,-30,-72,216).
-
# Exhibit 1
Hra := proc(r::integer,a::integer,q::integer)
binomial(r-1,a-1)*(q-3)+binomial(r-1,a) ;
%*(q-3)^(r-a-1) ;
end proc:
Jra := proc(r::integer,a::integer,q::integer)
binomial(r-2,a-2)*(q-3)^2 +2*binomial(r-2,a-1)*(q-3) +binomial(r-2,a) ;
%*(q-3)^(r-a-2) ;
end proc:
# Exhibit 2
A121124 := proc(r::integer)
q := 9 ;
a := 1 ;
Jra(r,a,q)+binomial(2,r-a)+( 1 +(-1)^(r+a) +(1+(-1)^a)*(1-(-1)^r)*floor((q-3)/2)/2)*Hra(floor(r/2),floor(a/2),q) ;
%/4 ;
end proc:
seq(A121124(n),n=2..30) # R. J. Mathar, Aug 01 2019
-
Join[{1, 4}, LinearRecurrence[{12, -30, -72, 216}, {21, 138, 864, 5526}, 22]] (* Jean-François Alcover, Apr 04 2020 *)
A304255
Triangle read by rows: T(0,0) = 1; T(n,k) = 6*T(n-1,k) + T(n-2,k-1) for k = 0..floor(n/2); T(n,k)=0 for n or k < 0.
Original entry on oeis.org
1, 6, 36, 1, 216, 12, 1296, 108, 1, 7776, 864, 18, 46656, 6480, 216, 1, 279936, 46656, 2160, 24, 1679616, 326592, 19440, 360, 1, 10077696, 2239488, 163296, 4320, 30, 60466176, 15116544, 1306368, 45360, 540, 1, 362797056, 100776960, 10077696, 435456, 7560, 36
Offset: 0
Triangle begins:
1;
6;
36, 1;
216, 12;
1296, 108, 1;
7776, 864, 18;
46656, 6480, 216, 1;
279936, 46656, 2160, 24;
1679616, 326592, 19440, 360, 1;
10077696, 2239488, 163296, 4320, 30;
60466176, 15116544, 1306368, 45360, 540, 1;
362797056, 100776960, 10077696, 435456, 7560, 36;
2176782336, 665127936, 75582720, 3919104, 90720, 756, 1;
13060694016, 4353564672, 554273280, 33592320, 979776, 12096, 42;
78364164096, 28298170368, 3990767616, 277136640, 9797760, 163296, 1008, 1;
470184984576, 182849716224, 28298170368, 2217093120, 92378880, 1959552, 18144, 48;
- Shara Lalo and Zagros Lalo, Polynomial Expansion Theorems and Number Triangles, Zana Publishing, 2018, ISBN: 978-1-9995914-0-3, pp. 70, 72, 94.
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t[0, 0] = 1; t[n_, k_] := If[n < 0 || k < 0, 0, 6 t[n - 1, k] + t[n - 2, k - 1]]; Table[t[n, k], {n, 0, 11}, {k, 0, Floor[n/2]}] // Flatten
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T(n, k) = if ((n<0) || (k<0), 0, if ((n==0) && (k==0), 1, 6*T(n-1, k) + T(n-2, k-1)));
tabf(nn) = for (n=0, nn, for (k=0, n\2, print1(T(n,k), ", ")); print); \\ Michel Marcus, May 26 2018
Showing 1-10 of 11 results.
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