OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
EXAMPLE
For n = 5; a(3) = 8, a(4) = 11, a(5) = 19 before [(8+11)*(8+19)*(11+19)] / (8+11+19) = 405 (integer).
MATHEMATICA
nxt[{a_, b_}]:= Module[{h = b + 1}, While[! IntegerQ[((a + b) (a + h) (b + h))/(a + b + h)], h++]; {b, h}]; Transpose[NestList[nxt, {1, 3}, 100]][[1]] (* G. C. Greubel, Jan 23 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Nov 28 2010
STATUS
approved