A050262 G.f.: ( 1 + x + x^2 - x^3 - x^4 - sqrt( 1 - 2 x - 5 x^2 - 4 x^3 - 3 x^4 - 4 x^5 - x^6 + 2 x^7 + x^8 ) ) / ( 2 x (1 + x) ).

1, 1, 1, 4, 10, 27, 79, 238, 736, 2322, 7445, 24190, 79470, 263534, 880966, 2965576, 10044096, 34202268, 117026156, 402139968, 1387243056, 4802307553, 16677543678, 58087052893, 202855613896, 710171007580, 2491870287323

Offset

0,4

Links

Robert Israel, Table of n, a(n) for n = 0..1761

Formula

D-finite with recurrence: (n-2)*a(n) + (-3+3*n)*a(1+n) + (n-2)*a(n+2) + (-11-5*n)*a(3+n) + (-22-7*n)*a(n+4) + (-34-7*n)*a(n+5) + (-57-9*n)*a(n+6) + (-52-7*n)*a(n+7) + (-7-n)*a(n+8) + (10+n)*a(n+9) = 0. - Robert Israel, Jan 15 2018

Maple

f:= gfun:-rectoproc({(n-2)*a(n)+(-3+3*n)*a(1+n)+(n-2)*a(n+2)+(-11-5*n)*a(3+n)+(-22-7*n)*a(n+4)+(-34-7*n)*a(n+5)+(-57-9*n)*a(n+6)+(-52-7*n)*a(n+7)+(-7-n)*a(n+8)+(10+n)*a(n+9), a(0) = 1, a(1) = 1, a(2) = 1, a(3) = 4, a(4) = 10, a(5) = 27, a(6) = 79, a(7) = 238, a(8) = 736}, a(n), remember):
map(f, [$0..50]); # Robert Israel, Jan 15 2018

Crossrefs

Sequence in context: A108672 A000495 A027067 * A295208 A222453 A186278

Adjacent sequences: A050259 A050260 A050261 * A050263 A050264 A050265

Keyword

easy,nonn

Author

Emanuele Munarini, May 09 2003

Status

approved