login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A309080 Product minus sum of all previous terms in the sequence, starting with a(1) = 2 and a(2) = 5. 1

%I

%S 2,5,3,20,570,341400,116758458000,13632577445813641200000,

%T 185847167817698504752014113195034069600000000,

%U 34539169785859790805229099212216829464451540660176789302662465332580254227520000000000000

%N Product minus sum of all previous terms in the sequence, starting with a(1) = 2 and a(2) = 5.

%F a(n) = Product_{k=1..n-1} a(k) - Sum_{k=1..n-1} a(k) with a(1) = 2, a(2) = 5.

%e a(4) = a(1)*a(2)*a(3) - (a(1) + a(2) + a(3)) = 2*5*3 - (2 + 5 + 3) = 20.

%t x1 = 2; x2 = 5; p = x1 * x2; s = x1 + x2; x = p - s; A309080 = {x1, x2, x}; Do[p = p * x; s = s + x; x = p - s; AppendTo[A309080, x], {n, 16}]

%o (Python)

%o a, n, p, s = [2,5], 2, 2, 2

%o while n < 10:

%o p, s, n = p*a[len(a)-1], s+a[len(a)-1], n+1

%o a = a+[p-s]

%o for n in range(1, 11): print(a[n-1], end=', ') # _A.H.M. Smeets_, Aug 22 2019

%Y Cf. A123702.

%K nonn

%O 1,1

%A _Christopher C. Capobianco_, Jul 11 2019

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 25 09:46 EDT 2022. Contains 356977 sequences. (Running on oeis4.)