A169652 a(1) = 5, a(n) = square of sum of previous terms.

5, 25, 900, 864900, 749661588900, 561993796031809299372900, 315837026779085485103717848762253067469831416900, 99753027484652761836825641888570160231510113731744254964202314837133807826801896930564374920900

Offset

1,1

Comments

sqrt(a(n+1)/a(n)) = A144780(n).

Links

Indranil Ghosh, Table of n, a(n) for n = 1..11

Formula

a(n+1) = [Sum_{i=1..n}{a(i)}]^2, with a(1)=5. [Paolo P. Lava, Apr 23 2010]

Maple

P:=proc(i) local a, s, n; print(5); s:=5; for n from 0 by 1 to i do a:=s^2; print(a); s:=s+a; od; end: P(100); # Paolo P. Lava, Apr 23 2010

Mathematica

lst={5}; Do[AppendTo[lst, Total[lst]^2], {10}]; lst (* Harvey P. Dale, Sep 28 2012 *)

Prog

(Python)
#Program to generate the b-file
lst=[5]
print("1 5")
i=2
a=sum(lst)**2
while i<=11:
    print(str(i)+" "+str(a))
    lst.append(a)
    i+=1
    a=sum(lst)**2 # Indranil Ghosh, Feb 20 2017

Crossrefs

Cf. A144780

Sequence in context: A176594 A274463 A279835 * A359232 A359235 A137114

Adjacent sequences: A169649 A169650 A169651 * A169653 A169654 A169655

Keyword

easy,nonn

Author

Giovanni Teofilatto, Apr 05 2010

Status

approved