A076843 Denominators of sequence of fractions defined by a(1) = a(2) = 1; for n > 2, a(n) = (a(n-1)+a(n-2)+1)/a(n-2).

1, 1, 1, 1, 1, 5, 15, 27, 261, 2059, 53321, 3826345, 599717165, 344730727333, 4379034727152233, 1299571503802595847199, 9181632264980134793594508931, 32308854341042109701936418652172579113, 67117797048843876734329361265492957492346044762131

Offset

1,6

Links

Table of n, a(n) for n=1..19.

Example

1, 1, 3, 5, 3, 9/5, 29/15, 71/27, 751/261, 5095/2059, 117707/53321, ...

Maple

a := 1; b := 1; f := proc(n) option remember; global a, b; if n=1 then RETURN(a); fi; if n=2 then RETURN(b); fi; RETURN((f(n-1)+f(n-2)+1)/f(n-2)); end;

Mathematica

Denominator[RecurrenceTable[{a[1]==a[2]==1, a[n]==(a[n-1]+a[n-2]+1)/ a[n-2]}, a, {n, 20}]] (* Harvey P. Dale, Jul 20 2014 *)

Crossrefs

Cf. A076842, A076844.

Sequence in context: A067533 A110343 A146060 * A285406 A129393 A268581

Adjacent sequences: A076840 A076841 A076842 * A076844 A076845 A076846

Keyword

nonn,frac

Author

N. J. A. Sloane, Nov 21 2002

Status

approved