OFFSET
0,2
LINKS
Ana Rechtman, Janvier 2015, 3ème défi, (in French), Images des Mathématiques, CNRS, 2015.
Ana Rechtman, Solution, (in French), Images des Mathématiques, CNRS, 2015.
FORMULA
a(n) = a(n-1) + a(n-2) + a(n-1)*a(n-2).
a(0) = 1 and a(n) = 2^Fibonacci(n)*3^Fibonacci(n+1) - 1 (see 2nd link).
a(n) == 8 mod 9, for n > 2. - Ivan N. Ianakiev, Jan 27 2015
EXAMPLE
a(0) = 1, a(1) = 2, a(2) = 1+2+(1*2) = 5, a(3) = 2+5+(2*5) = 17.
MATHEMATICA
a254132[0]=1; a254132[n_]:=2^Fibonacci[n-1]*3^Fibonacci[n]-1;
a254132/@Range[0, 11] (* Ivan N. Ianakiev, Jan 27 2015 *)
PROG
(PARI) lista(nn) = {x = 1; y = 2; print1(x, ", ", y, ", "); for (j=1, nn, z = x + y + x*y; print1(z, ", "); x = y; y = z; ); }
(PARI) a(n) = if (!n, 1, 2^fibonacci(n)*3^fibonacci(n+1) - 1);
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Jan 26 2015
STATUS
approved