A263045 a(1)=a(2)=1, a(3)=2; for n>3, a(n) = (a(n-1) + a(n-2))*a(n-3) - a(n-1).

1, 1, 2, 1, 2, 4, 2, 10, 38, 58, 902, 35578, 2080262, 1906407418, 67898268271622, 141250085279900836858, 269280339671247778784817867782, 18283668752862244903904463537467802693858298, 2582569770571288306580588933602503511656010789600193877369998342

Offset: 1

Author

Gianmarco Giordano, Oct 08 2015

Keywords

• nonn

Programs

Magma

I:=[1,1,2]; [n le 3 select I[n]  else (Self(n-1)+ Self(n-2))*Self(n-3)-Self(n-1): n in [1..20]]; // Vincenzo Librandi, Oct 09 2015

Mathematica

RecurrenceTable[{a[1]==a[2]==1,a[3]==2,a[n]==(a[n-1]+a[n-2])a[n-3]-a[n-1]}, a,{n,20}] (* Harvey P. Dale, Jul 23 2018 *)

PARI

a(n) = if(n<4, fibonacci(n), (a(n-1)+a(n-2))*a(n-3)-a(n-1)) \\ Altug Alkan, Oct 08 2015

Extensions

More terms from Altug Alkan, Oct 08 2015