A170801 -id:A170801 - cp's OEIS frontend

A277504 Array read by descending antidiagonals: T(n,k) is the number of unoriented strings with n beads of k or fewer colors.

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 1, 0, 1, 4, 6, 6, 1, 0, 1, 5, 10, 18, 10, 1, 0, 1, 6, 15, 40, 45, 20, 1, 0, 1, 7, 21, 75, 136, 135, 36, 1, 0, 1, 8, 28, 126, 325, 544, 378, 72, 1, 0, 1, 9, 36, 196, 666, 1625, 2080, 1134, 136, 1, 0, 1, 10, 45, 288, 1225, 3996, 7875, 8320, 3321, 272, 1, 0

Offset: 0

Jean-François Alcover, Oct 18 2016

From Petros Hadjicostas, Jul 07 2018: (Start)
Column k of this array is the "BIK" (reversible, indistinct, unlabeled) transform of k,0,0,0,....
Consider the input sequence (c_k(n): n >= 1) with g.f. C_k(x) = Sum_{n>=1} c_k(n)*x^n. Let a_k(n) = BIK(c_k(n): n >= 1) be the output sequence under Bower's BIK transform. It can proved that the g.f. of BIK(c_k(n): n >= 1) is A_k(x) = (1/2)*(C_k(x)/(1-C_k(x)) + (C_k(x^2) + C_k(x))/(1-C_k(x^2))). (See the comments for sequence A001224.)
For column k of this two-dimensional array, the input sequence is defined by c_k(1) = k and c_k(n) = 0 for n >= 1. Thus, C_k(x) = k*x, and hence the g.f. of column k is (1/2)*(C_k(x)/(1-C_k(x)) + (C_k(x^2) + C_k(x))/(1-C_k(x^2))) = (1/2)*(k*x/(1-k*x) + (k*x^2 + k*x)/(1-k*x^2)) = (2 + (1-k)*x - 2*k*x^2)*k*x/(2*(1-k*x^2)*(1-k*x)).
Using the first form the g.f. above and the expansion 1/(1-y) = 1 + y + y^2 + ..., we can easily prove J.-F. Alcover's formula T(n,k) = (k^n + k^((n + mod(n,2))/2))/2.
(End)

			Array begins with T(0,0):
1 1   1     1      1       1        1         1         1          1 ...
0 1   2     3      4       5        6         7         8          9 ...
0 1   3     6     10      15       21        28        36         45 ...
0 1   6    18     40      75      126       196       288        405 ...
0 1  10    45    136     325      666      1225      2080       3321 ...
0 1  20   135    544    1625     3996      8575     16640      29889 ...
0 1  36   378   2080    7875    23436     58996    131328     266085 ...
0 1  72  1134   8320   39375   140616    412972   1050624    2394765 ...
0 1 136  3321  32896  195625   840456   2883601   8390656   21526641 ...
0 1 272  9963 131584  978125  5042736  20185207  67125248  193739769 ...
0 1 528 29646 524800 4884375 30236976 141246028 536887296 1743421725 ...
...

See A005418.

Robert A. Russell, Antidiagonals n=0..52, flattened (antidiagonals 1..50 from Andrew Howroyd)
C. G. Bower, Transforms (2)

Columns 0-6 are A000007, A000012, A005418(n+1), A032120, A032121, A032122, A056308.
Rows 0-20 are A000012, A001477, A000217 (triangular numbers), A002411 (pentagonal pyramidal numbers), A037270, A168178, A071232, A168194, A071231, A168372, A071236, A168627, A071235, A168663, A168664, A170779, A170780, A170790, A170791, A170801, A170802.
Main diagonal is A275549.
Transpose is A284979.
Cf. A284871, A284949.
Cf. A003992 (oriented), A293500 (chiral), A321391 (achiral).

[[n le 0 select 1 else ((n-k)^k + (n-k)^Ceiling(k/2))/2: k in [0..n]]: n in [0..15]]; // G. C. Greubel, Nov 15 2018

Table[If[n>0, ((n-k)^k + (n-k)^Ceiling[k/2])/2, 1], {n, 0, 15}, {k, 0, n}] // Flatten (* updated Jul 10 2018 *) (* Adapted to T(0,k)=1 by Robert A. Russell, Nov 13 2018 *)

for(n=0,15, for(k=0,n, print1(if(n==0,1, ((n-k)^k + (n-k)^ceil(k/2))/2), ", "))) \\ G. C. Greubel, Nov 15 2018

T(n,k) = {(k^n + k^ceil(n/2)) / 2} \\ Andrew Howroyd, Sep 13 2019

T(n,k) = [n==0] + [n>0] * (k^n + k^ceiling(n/2)) / 2. [Adapted to T(0,k)=1 by Robert A. Russell, Nov 13 2018]
G.f. for column k: (1 - binomial(k+1,2)*x^2) / ((1-k*x)*(1-k*x^2)). - Petros Hadjicostas, Jul 07 2018 [Adapted to T(0,k)=1 by Robert A. Russell, Nov 13 2018]
From Robert A. Russell, Nov 13 2018: (Start)
T(n,k) = (A003992(k,n) + A321391(n,k)) / 2.
T(n,k) = A003992(k,n) - A293500(n,k) = A293500(n,k) + A321391(n,k).
G.f. for row n: (Sum_{j=0..n} S2(n,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=0..ceiling(n/2)} S2(ceiling(n/2),j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f. for row n>0: x*Sum_{k=0..n-1} A145882(n,k) * x^k / (1-x)^(n+1).
E.g.f. for row n: (Sum_{k=0..n} S2(n,k)*x^k + Sum_{k=0..ceiling(n/2)} S2(ceiling(n/2),k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
T(0,k) = 1; T(1,k) = k; T(2,k) = binomial(k+1,2); for n>2, T(n,k) = k*(T(n-3,k)+T(n-2,k)-k*T(n-1,k)).
For k>n, T(n,k) = Sum_{j=1..n+1} -binomial(j-n-2,j) * T(n,k-j). (End)

Array transposed for greater consistency by Andrew Howroyd, Apr 04 2017

Origin changed to T(0,0) by Robert A. Russell, Nov 13 2018

A170798 a(n) = n^10*(n^6 + 1)/2.

Original entry on oeis.org

0, 1, 33280, 21552885, 2148007936, 76298828125, 1410585186816, 16616606522425, 140738025226240, 926511837818121, 5000005000000000, 22974877900498381, 92442160406200320, 332708373520835845, 1088976813532013056

Offset: 0

N. J. A. Sloane, Dec 11 2009

a(n) is number of distinct 4 X 4 matrices with entries in {1,2,...,n} when a matrix and its transpose are considered equivalent. - David Nacin, Feb 20 2017

Cycle index of this S2 group action is (s(2)^6s(1)^4+s(1)^16)/2. - David Nacin, Feb 20 2017

			a(2) = 33280 is the number of inequivalent 4 X 4 binary matrices up to taking the transpose. - _David Nacin_, Feb 20 2017

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (17,-136,680,-2380,6188,-12376,19448,-24310,24310,-19448,12376,-6188,2380,-680,136,-17,1).

Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), A170796 (m=4), A170797 (m=5), this sequence (m=6), A170799 (m=7), A170800 (m=8), A170801 (m=9), A170802 (m=10).

List([0..20], n-> n^10*(n^6 +1)/2); # G. C. Greubel, Oct 11 2019

[n^10*(n^6+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 27 2011

seq(n^10*(n^6+1)/2, n=0..20); # G. C. Greubel, Oct 12 2019

Table[n^10*(n^6+1)/2,{n,0,30}] (* Harvey P. Dale, Aug 27 2016 *)

concat(0, Vec(-x*(x +1)*(x^14 +33262*x^13 +20953999*x^12 +1765180292*x^11 +40926077261*x^10 +350131349138*x^9 +1253612167971*x^8 +1937785948152*x^7 +1253612167971*x^6 +350131349138*x^5 +40926077261*x^4 +1765180292*x^3 +20953999*x^2 +33262*x +1) / (x -1)^17 + O(x^30))) \\ Colin Barker, Jul 11 2015

vector(21, m, (m-1)^10*((m-1)^6 + 1)/2) \\ G. C. Greubel, Oct 11 2019

[n^10*(n^6 +1)/2 for n in (0..20)] # G. C. Greubel, Oct 11 2019

G.f.: x*(x+1)*(x^14 + 33262*x^13 + 20953999*x^12 + 1765180292*x^11 + 40926077261*x^10 + 350131349138*x^9 + 1253612167971*x^8 + 1937785948152*x^7 + 1253612167971*x^6 + 350131349138*x^5 + 40926077261*x^4 + 1765180292*x^3 + 20953999*x^2 + 33262*x + 1)/(1-x)^17. - Colin Barker, Jul 11 2015

E.g.f.: x*(2 + 33278*x + 7151016*x^2 + 171833006*x^3 + 1096233075*x^4 + 2734949385*x^5 + 3281888484*x^6 + 2141764803*x^7 + 820784295*x^8 + 193754991*x^9 + 28936908*x^10 + 2757118*x^11 + 165620*x^12 + 6020*x^13 + 120*x^14 + x^15)*exp(x)/2. - G. C. Greubel, Oct 12 2019

A170802 a(n) = n^10*(n^10 + 1)/2.

Original entry on oeis.org

0, 1, 524800, 1743421725, 549756338176, 47683720703125, 1828079250264576, 39896133290043625, 576460752840294400, 6078832731271856601, 50000000005000000000, 336374997479248716901, 1916879996254696243200

Offset: 0

N. J. A. Sloane, Dec 11 2009

By definition, all terms are triangular numbers. - Harvey P. Dale, Aug 12 2012

Number of unoriented rows of length 20 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=524800, there are 2^20=1048576 oriented arrangements of two colors. Of these, 2^10=1024 are achiral. That leaves (1048576-1024)/2=523776 chiral pairs. Adding achiral and chiral, we get 524800. - Robert A. Russell, Nov 13 2018

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (21, -210, 1330, -5985, 20349, -54264, 116280, -203490, 293930, -352716, 352716, -293930, 203490, -116280, 54264, -20349, 5985, -1330, 210, -21, 1).

Row 20 of A277504.
Cf. A010808 (oriented), A008454 (achiral).
Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), A170896 (m=4), A170797 (m=5), A170798 (m=6), A170799 (m=7), A170800 (m=8), A170801 (m=9), this sequence (m=10).

List([0..30], n -> n^10*(n^10+1)/2); # G. C. Greubel, Nov 15 2018

[n^10*(n^10+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 27 2011

seq(n^10*(n^10 +1)/2, n=0..20); # G. C. Greubel, Oct 11 2019

n10[n_]:=Module[{c=n^10},(c(c+1))/2];Array[n10,15,0] (* Harvey P. Dale, Jul 17 2012 *)

vector(30, n, n--; n^10*(n^10+1)/2) \\ G. C. Greubel, Nov 15 2018

for n in range(0,20): print(int(n**10*(n**10 + 1)/2), end=', ') # Stefano Spezia, Nov 15 2018

[n^10*(n^10+1)/2 for n in range(30)] # G. C. Greubel, Nov 15 2018

From Robert A. Russell, Nov 13 2018: (Start)
a(n) = (A010808(n) + A008454(n)) / 2 = (n^20 + n^10) / 2.
G.f.: (Sum_{j=1..20} S2(20,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..10} S2(10,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f.: x*Sum_{k=0..19} A145882(20,k) * x^k / (1-x)^21.
E.g.f.: (Sum_{k=1..20} S2(20,k)*x^k + Sum_{k=1..10} S2(10,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
For n>20, a(n) = Sum_{j=1..21} -binomial(j-22,j) * a(n-j). (End)

A170797 a(n) = n^10*(n^5+1)/2.

Original entry on oeis.org

0, 1, 16896, 7203978, 537395200, 15263671875, 235122725376, 2373921992596, 17592722915328, 102947309439525, 500005000000000, 2088637053420126, 7703541745975296, 25593015436291303, 77784192406233600

Offset: 0

N. J. A. Sloane, Dec 11 2009

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (16,-120,560,-1820,4368,-8008,11440,-12870,11440,-8008,4368,-1820,560,-120,16,-1).

Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), A170796 (m=4), this sequence (m=5), A170798 (m=6), A170799 (m=7), A170800 (m=8), A170801 (m=9), A170802 (m=10).

List([0..20], n-> n^10*(n^5 +1)/2); # G. C. Greubel, Oct 11 2019

[n^10*(n^5+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 26 2011

A170797:=n->n^10*(n^5+1)/2: seq(A170797(n), n=0..20); # Wesley Ivan Hurt, Aug 10 2016

Table[n^10*(n^5 + 1)/2, {n, 0, 15}] (* Wesley Ivan Hurt, Aug 10 2016 *)

vector(21, m, (m-1)^10*((m-1)^5 + 1)/2) \\ G. C. Greubel, Oct 11 2019

[n^10*(n^5 +1)/2 for n in (0..20)] # G. C. Greubel, Oct 11 2019

G.f.: x*(15872*x^13 +6890977*x^12 +423932400*x^11 +7520863426*x^10 +51389080880*x^9 +155692452591*x^8 +223769408736*x^7 +155695145820*x^6 +51387918048*x^5 +7520366095*x^4 +424158512*x^3 +6933762*x^2 +16880*x +1) / (x-1)^16. - Colin Barker, Nov 01 2014
a(n) = 16*a(n-1) - 120*a(n-2) + 560*a(n-3) - 1820*a(n-4) + 4368*a(n-5) - 8008*a(n-6) + 11440*a(n-7) - 12870*a(n-8) + 11440*a(n-9) - 8008*a(n-10) + 4368*a(n-11) - 1820*a(n-12) + 560*a(n-13) - 120*a(n-14) + 16*a(n-15) - a(n-16) for n > 15. - Wesley Ivan Hurt, Aug 10 2016
E.g.f.: x*(2 +16894*x +2384431*x^2 +42390055*x^3 +210809445*x^4 + 420716100*x^5 +408747213*x^6 +216628590*x^7 +67128535*x^8 +12662651*x^9 +1479478*x^10 +106470*x^11 +4550*x^12 +105*x^13 +x^14)*exp(x)/2. - G. C. Greubel, Oct 11 2019

A170799 a(n) = n^10*(n^7 + 1)/2.

Original entry on oeis.org

0, 1, 66048, 64599606, 8590458880, 381474609375, 8463359955456, 116315398231228, 1125900443713536, 8338592593225485, 50000005000000000, 252723527218359186, 1109305584328900608, 4325208028619914891, 15245673509292925440, 49263062956171875000, 147573953139432226816

Offset: 0

N. J. A. Sloane, Dec 11 2009

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (18,-153,816,-3060,8568,-18564,31824,-43758,48620,-43758,31824,-18564,8568,-3060,816,-153,18,-1).

Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), A170796 (m=4), A170797 (m=5), A170798 (m=6), this sequence (m=7), A170800 (m=8), A170801 (m=9), A170802 (m=10).

List([0..20], n-> n^10*(n^7 +1)/2); # G. C. Greubel, Oct 11 2019

[n^10*(n^7+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 27 2011

seq(n^10*(n^7 +1)/2, n=0..20); # G. C. Greubel, Oct 11 2019

Table[n^10(n^7+1)/2,{n,0,20}] (* Harvey P. Dale, Aug 27 2013 *)

vector(21, m, (m-1)^10*((m-1)^7 + 1)/2) \\ G. C. Greubel, Oct 11 2019

[n^10*(n^7 +1)/2 for n in (0..20)] # G. C. Greubel, Oct 11 2019

G.f.: x*(65024*x^15 + 63370125*x^14 + 7437628950*x^13 + 236677103915*x^12 + 2858645957220*x^11 + 15527824213413*x^10 + 41568614867330*x^9 + 57445190329275*x^8 + 41568608318040*x^7 + 15527828734975*x^6 + 2858646015162*x^5 + 236676197145*x^4 + 7437770500*x^3 + 63410895*x^2 + 66030*x + 1)/(x-1)^18. - Colin Barker, Feb 24 2013

E.g.f.: x*(2 + 66046*x + 21467155*x^2 + 694371395*x^3 + 5652794176*x^4 + 17505772725*x^5 + 25708110666*x^6 + 20415995778*x^7 + 9528822348*x^8 + 2758334151*x^9 + 512060978*x^10 + 62022324*x^11 + 4910178*x^12 + 249900*x^13 + 7820*x^14 + 136*x^15 + x^16)*exp(x)/2. - G. C. Greubel, Oct 12 2019

A170800 a(n) = n^10*(n^8 + 1)/2.

Original entry on oeis.org

0, 1, 131584, 193739769, 34360262656, 1907353515625, 50780008567296, 814206940192849, 9007199791611904, 75047319391891761, 500000005000000000, 2779958669714828041, 13311666671401304064, 56227703544907942489

Offset: 0

N. J. A. Sloane, Dec 11 2009

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (19,-171,969,-3876,11628,-27132,50388,-75582,92378,-92378,75582,-50388,27132,-11628,3876,-969,171,-19,1).

Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), A170796 (m=4), A170797 (m=5), A170798 (m=6), A170799 (m=7), this sequence (m=8), A170801 (m=9), A170802 (m=10).

List([0..20], n-> n^10*(n^8 +1)/2); # G. C. Greubel, Oct 11 2019

[n^10*(n^8+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 27 2011

seq(n^10*(n^8 +1)/2, n=0..20); # G. C. Greubel, Oct 11 2019

Table[n^10 (n^8+1)/2,{n,0,20}] (* Harvey P. Dale, Jul 14 2013 *)

vector(21, m, (m-1)^10*((m-1)^8 + 1)/2) \\ G. C. Greubel, Oct 11 2019

[n^10*(n^8 +1)/2 for n in (0..20)] # G. C. Greubel, Oct 11 2019

G.f.: x*(1 + 131565*x + 191239844*x^2 + 30701706940*x^3 + 1287510524640*x^4 + 20228672856392*x^5 + 142998539385460*x^6 + 503354978422188*x^7 + 932692832164970*x^8 + 932692832164970*x^9 + 503354978422188*x^10 + 142998539385460*x^11 + 20228672856392*x^12 + 1287510524640*x^13 + 30701706940*x^14 +191239844*x^15 + 131565*x^16 + x^17)/(1-x)^19. - Harvey P. Dale, Jul 14 2013

E.g.f.: x*(2 + 131582*x + 64448340*x^2 + 2798841090*x^3 + 28958138070*x^4 + 110687273866*x^5 + 197462489280*x^6 + 189036065760*x^7 + 106175395800*x^8 + 37112163804*x^9 + 8391004908*x^10 + 1256328866*x^11 + 125854638*x^12 + 8408778*x^13 + 367200*x^14 + 9996*x^15 + 153*x^16 + x^17)*exp(x)/2. - G. C. Greubel, Oct 12 2019

A170796 a(n) = n^10*(n^4 + 1)/2.

Original entry on oeis.org

0, 1, 8704, 2421009, 134742016, 3056640625, 39212315136, 339252774049, 2199560126464, 11440139619681, 50005000000000, 189887885503921, 641990190956544, 1968757122095569, 5556148040106496, 14596751337890625

Offset: 0

N. J. A. Sloane, Dec 11 2009

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (15,-105,455,-1365,3003,-5005,6435,-6435,5005,-3003,1365,-455,105,-15,1).

Sequences of the form n^10*(n^m + 1)/2: A170793 (m=1), A170794 (m=2), A170795 (m=3), this sequence (m=4), A170797 (m=5), A170798 (m=6), A170799 (m=7), A170800 (m=8), A170801 (m=9), A170802 (m=10).

List([0..20], n-> n^10*(n^4 +1)/2); # G. C. Greubel, Oct 11 2019

[n^10*(n^4+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 26 2011

seq(n^10*(n^4 +1)/2, n=0..20); # G. C. Greubel, Oct 11 2019

Table[n^10*(n^4 +1)/2, {n,0,20}] (* G. C. Greubel, Oct 11 2019 *)

vector(21, m, (m-1)^10*((m-1)^4 + 1)/2) \\ G. C. Greubel, Oct 11 2019

[n^10*(n^4 +1)/2 for n in (0..20)] # G. C. Greubel, Oct 11 2019

From G. C. Greubel, Oct 11 2019: (Start)
G.f.: x*(1 +8689*x +2290554*x^2 +99340346*x^3 +1285757375*x^4 +6420936303*x^5 +13986239532*x^6 +13986239532*x^7 +6420936303*x^8 +1285757375*x^9 +99340346*x^10 +2290554*x^11 +8689*x^12 +x^13)/(1-x)^15.
E.g.f.: x*(2 +8702*x +798300*x^2 +10425850*x^3 +40117560*x^4 +63459200*x^5 +49335160*x^6 +20913070*x^7 +5135175*x^8 +752753*x^9 + 66066*x^10 +3367*x^11 +91*x^12 +x^13)*exp(x)/2. (End)

cp's OEIS Frontend

A277504 Array read by descending antidiagonals: T(n,k) is the number of unoriented strings with n beads of k or fewer colors.

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A170798 a(n) = n^10*(n^6 + 1)/2.

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A170802 a(n) = n^10*(n^10 + 1)/2.

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A170797 a(n) = n^10*(n^5+1)/2.

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Sage

Formula

A170799 a(n) = n^10*(n^7 + 1)/2.

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GAP

Magma

Maple

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PARI

Sage

Formula

A170800 a(n) = n^10*(n^8 + 1)/2.

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