A277411 Column 1 of triangle A277410.

0, 3, 13, 38, 94, 213, 459, 960, 1972, 4007, 8089, 16266, 32634, 65385, 130903, 261956, 524080, 1048347, 2096901, 4194030, 8388310, 16776893, 33554083, 67108488, 134217324, 268435023, 536870449, 1073741330, 2147483122, 4294966737, 8589933999, 17179868556, 34359737704, 68719476035, 137438952733, 274877906166, 549755813070, 1099511626917, 2199023254651, 4398046510160

Offset

1,2

Links

Table of n, a(n) for n=1..40.

Formula

Conjectures from Colin Barker, Nov 04 2016: (Start)

G.f.: x^2*(3-2*x) / ((1-x)^3*(1-2*x)).

a(n) = 5*a(n-1)-9*a(n-2)+7*a(n-3)-2*a(n-4) for n>4.

a(n) = (8*(2^n-1)-n*(n+7))/2. (End)

Prog

(PARI) {A277410(n, k) = my(A=x); for(i=1, n, A = x + subst(intformal(A +x*O(x^n)), x, y*A + (1-y)*x ) ); n!*polcoeff(polcoeff(A, n, x), k, y)}
for(n=1, 30, print1(A277410(n+1, 1), ", "));

Crossrefs

Cf. A277410, A277412.

Sequence in context: A019007 A147554 A076800 * A054975 A072790 A323009

Adjacent sequences: A277408 A277409 A277410 * A277412 A277413 A277414

Keyword

nonn

Author

Paul D. Hanna, Oct 25 2016

Status

approved