OFFSET
1,1
COMMENTS
A217663(n) = a(n+2)/a(n)-1 consists of 1's and primes only.
FORMULA
For prime p > 2, a(p+1) = (p+1)*a(p-1), which proves the statement in A217663. - M. F. Hasler, Oct 11 2012
MATHEMATICA
RecurrenceTable[{a[n]==a[n-2]+LCM[n-1, a[n-2]], a[1] == 2, a[2]==2}, a, {n, 1, 24}]
t = {2, 2}; Do[AppendTo[t, t[[-2]] + LCM[n-1, t[[-2]]]], {n, 3, 40}]; t (* T. D. Noe, Oct 10 2012 *)
nxt[{n_, a_, b_}]:={n+1, b, a+LCM[a, n]}; NestList[nxt, {2, 2, 2}, 40][[All, 2]] (* Harvey P. Dale, Aug 20 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Pedja Terzic, Oct 10 2012
STATUS
approved