A174811 A (100,-196) Somos 4 sequence.

1, 3, 26, 836, 118304, 56868928, 77348401664, 336344302104576, 6256170906514948096, 461016146852019430227968, 101290253760680508433761304576, 64552542594684734744030356172701696

Offset

0,2

Comments

Hankel transform of A174810.

Links

G. C. Greubel, Table of n, a(n) for n = 0..60

Formula

a(n) = (100*a(n-1)*a(n-3) - 196*a(n-2)^2)/a(n-4), n>3.

Mathematica

nxt[{a_, b_, c_, d_}]:={b, c, d, (100*d*b-196c^2)/a}; Transpose[ NestList[ nxt, {1, 3, 26, 836}, 12]][[1]] (* Harvey P. Dale, Jun 20 2015 *)
RecurrenceTable[{a[n] == (100*a[n-1]*a[n-3] -196*a[n-2]^2)/a[n-4], a[0] == 1, a[1] == 3, a[2] == 26, a[3] == 836}, a, {n, 0, 30}] (* G. C. Greubel, Sep 25 2018 *)

Prog

(PARI) m=30; v=concat([1, 3, 26, 836], vector(m-4)); for(n=5, m, v[n] = ( 100*v[n-1]*v[n-3] - 196*v[n-2]^2)/v[n-4]); v \\ G. C. Greubel, Sep 25 2018
(Magma) I:=[1, 3, 26, 836]; [n le 4 select I[n] else (100*Self(n-1)*Self(n-3) - 196*Self(n-2)^2)/Self(n-4): n in [1..30]]; // G. C. Greubel, Sep 25 2018

Crossrefs

Sequence in context: A101613 A280222 A354652 * A214808 A219895 A088730

Adjacent sequences: A174808 A174809 A174810 * A174812 A174813 A174814

Keyword

easy,nonn

Author

Paul Barry, Mar 29 2010

Status

approved