A094212 Duplicate of A070832.
1, 2, 12872, 1470944, 622116992, 125858012672, 36758056208384
Offset: 0
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a := n -> if n = 0 then 1 else 4^(n - 1)*(2*(-1)^n + 4^n) fi: seq(a(n), n = 0..19); # Peter Luschny, Jul 02 2022
Table[Sum[Binomial[4n,4k],{k,0,n}],{n,0,30}] (* or *) Join[{1}, LinearRecurrence[{12,64},{2,72},30]] (* Harvey P. Dale, Apr 24 2011 *)
a(n)=sum(k=0,n,binomial(4*n,4*k))
N=66; x='x+O('x^N); Vec((1-10*x-16*x^2)/((1-16*x)*(1+4*x))) \\ Seiichi Manyama, Mar 15 2019
LinearRecurrence[{21,353,-32},{1,2,254},20] (* Harvey P. Dale, Jun 18 2023 *)
a(n)=sum(k=0,n,binomial(5*n,5*k))
Vec((1 - 19*x - 141*x^2) / ((1 - 32*x)*(1 + 11*x - x^2)) + O(x^20)) \\ Colin Barker, May 27 2019
Table[Sum[Binomial[6n,6k],{k,0,n}],{n,0,20}] (* or *) LinearRecurrence[ {38,1691,-1728},{1,2,926,37130},30] (* Harvey P. Dale, Jun 19 2021 *)
a(n)=sum(k=0,n,binomial(6*n,6*k))
a(n)=if(n<0,0,(2*(-27)^n+2+64^n+0^n)/6)
a(n)=if(n<0,0,polsym(x*(x-64)*(x+27)^2*(x-1)^2,n)[n+1]/6)
a(n) = sum(k=0, n, binomial(10*n, 10*k)); \\ Michel Marcus, Mar 15 2019
Vec((1 - 520*x - 404083*x^2 + 37605988*x^3 + 117888625*x^4 - 320000*x^5) / ((1 - 1024*x)*(1 - 123*x + x^2)*(1 + 625*x + 3125*x^2)) + O(x^15)) \\ Colin Barker, Mar 15 2019
A094211:=n->add(binomial(7*n,7*k), k=0..n): seq(A094211(n), n=0..20); # Wesley Ivan Hurt, Feb 16 2017
Table[Sum[Binomial[7n,7k],{k,0,n}],{n,0,20}] (* or *) LinearRecurrence[ {71,7585,-36991,-128},{1,2,3434,232562},20] (* Harvey P. Dale, May 06 2012 *)
a(n)=sum(k=0,n,binomial(7*n,7*k))
Table[Sum[Binomial[9n,9k],{k,0,n}],{n,0,15}] (* Harvey P. Dale, Jul 14 2019 *)
a(n)=sum(k=0,n,binomial(9*n,9*k))
Vec((1 - 263*x - 91731*x^2 + 3035380*x^3 + 1547833*x^4) / ((1 + x)*(1 - 512*x)*(1 + 246*x - 13605*x^2 + x^3)) + O(x^15)) \\ Colin Barker, May 27 2019
Array A(n, k) starts: [0] 1, 2, 3, 4, 5, 6, 7, ... A000027 [1] 1, 2, 4, 8, 16, 32, 64, ... A000079 [2] 1, 2, 8, 32, 128, 512, 2048, ... A081294 [3] 1, 2, 22, 170, 1366, 10922, 87382, ... A007613 [4] 1, 2, 72, 992, 16512, 261632, 4196352, ... A070775 [5] 1, 2, 254, 6008, 215766, 6643782, 215492564, ... A070782 [6] 1, 2, 926, 37130, 2973350, 174174002, 11582386286, ... A070967 [7] 1, 2, 3434, 232562, 42484682, 4653367842, 644032289258, ... A094211 . Triangle T(n, k) starts: [0] 1; [1] 2, 1; [2] 3, 2, 1; [3] 4, 4, 2, 1; [4] 5, 8, 8, 2, 1; [5] 6, 16, 32, 22, 2, 1; [6] 7, 32, 128, 170, 72, 2, 1; [7] 8, 64, 512, 1366, 992, 254, 2, 1; [8] 9, 128, 2048, 10922, 16512, 6008, 926, 2, 1; [9] 10, 256, 8192, 87382, 261632, 215766, 37130, 3434, 2, 1; . A(2, 2) = 8 = card(0000, 1100, 1010, 1001, 0110, 0101, 0011, 1111). A(1, 3) = 8 = card(000, 100, 010, 001, 110, 101, 011, 111).
T := (n, k) -> add(binomial((n - k)*k, j*k), j = 0 .. n-k): seq(print(seq(T(n, k), k = 0..n)), n = 0..7);
# In Python use this import: # from sympy.utilities.iterables import multiset_permutations def A(n: int, k: int) -> int: if n == 0: return k + 1 count = 0 for a in range(0, n * k + 1, n): S = [i < a for i in range(n * k)] count += Permutations(S).cardinality() return count def ARow(n: int, size: int) -> list[int]: return [A(n, k) for k in range(size)] for n in range(6): print(ARow(n, 5))
Square array begins: 1, 1, 1, 1, 1, 1, ... 2, 2, 2, 2, 2, 2, ... 3, 4, 8, 22, 72, 254, ... 4, 8, 32, 170, 992, 6008, ... 5, 16, 128, 1366, 16512, 215766, ... 6, 32, 512, 10922, 261632, 6643782, ... 7, 64, 2048, 87382, 4196352, 215492564, ...
T[n_, k_] := Sum[Binomial[k*n, k*j], {j, 0, n}] ; Table[T[k, n - k], {n, 0, 10}, {k, 0, n}] // Flatten (* Amiram Eldar, May 12 2021 *)
Comments
. - Sean A. Irvine, Nov 09 2024