A258143 Row sums of A257241, Stifel's version of the arithmetical triangle.
1, 2, 6, 10, 25, 41, 98, 162, 381, 637, 1485, 2509, 5811, 9907, 22818, 39202, 89845, 155381, 354521, 616665, 1401291, 2449867, 5546381, 9740685, 21977515, 38754731, 87167163, 154276027, 345994215, 614429671, 1374282018, 2448023842, 5461770405, 9756737701, 21717436833
Offset: 1
Examples
n=3: a(3) = 2^3 - (1 + A008549(1)) = 8 - (1 + 1) = 6. n=4: a(4) = 2^4 - (1 + A000346(1)) = 16 - (1 + 5) = 10.
Links
- Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
Programs
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Haskell
a258143 = sum . a257241_row -- Reinhard Zumkeller, May 22 2015
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Mathematica
Table[Sum[Binomial[n, m], {m, Ceiling[n/2]}], {n, 50}] (* Paolo Xausa, Nov 14 2024 *)
Formula
a(n) = Sum_{m = 1 .. ceiling(n/2)} binomial(n, m), n >= 1.
a(n) = 2^n - 2 - Sum_{i=1..floor(n/2)-1} binomial(n, i), n >= 2; a(1)=1. - Enrique Navarrete, Dec 16 2019
a(2*k+1) = 2^(2*k+1) - (1 + A008549(k)), k >= 0.
a(2*k) = 2^(2*k) - (1 + A000346(k-1)), k >= 1.
O.g.f.: x*(2+3*x+x^2 - (1-x^2)*(1+x)*c(x^2))/((1-(2*x)^2)*(1-x^2)) where c(x) is the o.g.f. of A000108.
O.g.f. for a(2*k+1), k >= 0: (2+x - (1-x)*c(x))/ ((1-4*x)*(1-x)).
O.g.f. for a(2*(k+1)), k >= 0: (3 - (1-x)*c(x))/ ((1-4*x)*(1-x)).
a(n) = A116406(n+1) - 1. - Hugo Pfoertner, Nov 14 2024
Comments