A213572 Principal diagonal of the convolution array A213571.

1, 13, 82, 406, 1809, 7659, 31588, 128476, 518611, 2084809, 8361918, 33497010, 134094757, 536608663, 2146926472, 8588754808, 34357247847, 137433710421, 549744803650, 2199000186670, 8796044787481, 35184271425283

Offset: 1

Author

Clark Kimberling, Jun 19 2012

Keywords

• nonn
• easy

Links

• Clark Kimberling, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (11,-47,101,-116,68,-16).

Crossrefs

Cf. A213571, A213500.

Programs

GAP

List([1..30], n-> 2^(2*n+1) -2^n*(n+2) -Binomial(n+1, 2)); # G. C. Greubel, Jul 25 2019

Magma

[2^(2*n+1) -2^n*(n+2) -Binomial(n+1, 2): n in [1..30]]; // G. C. Greubel, Jul 25 2019

Mathematica

(* First program *)
b[n_]:= n; c[n_]:= -1 + 2^n;
t[n_, k_]:= Sum[b[k-i] c[n+i], {i, 0, k-1}]
TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]]
Flatten[Table[t[n-k+1, k], {n, 12}, {k, n, 1, -1}]]
r[n_]:= Table[t[n, k], {k, 1, 60}]  (* A213571 *)
d = Table[t[n, n], {n, 1, 40}] (* A213572 *)
s[n_]:= Sum[t[i, n+1-i], {i, 1, n}]
s1 = Table[s[n], {n, 1, 50}] (* A213581 *)
(* Additional programs *)
Table[2^(2*n+1) -2^n*(n+2)-Binomial[n+1, 2], {n,30}] (* G. C. Greubel, Jul 25 2019 *)

PARI

vector(30, n, 2^(2*n+1) -2^n*(n+2) -binomial(n+1, 2)) \\ G. C. Greubel, Jul 25 2019

Sage

[2^(2*n+1) -2^n*(n+2) -binomial(n+1, 2) for n in (1..30)] # G. C. Greubel, Jul 25 2019

Formula

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

a(n) = 11*a(n-1) - 47*a(n-2) + 101*a(n-3) - 116*a(n-4) + 68*a(n-5) - 16*a(n-6).

G.f.: f(x)/g(x), where f(x) = x*(1 + 2*x - 14*x^2 + 14*x^3) and g(x) = (1 - 4*x)*((1 - x)^3)*(1 - 2*x)^2.