billionth Recaman

[Don Reble]

> ...to compute the first billion terms on one of our large machines.

    Ok. To do that, you may need a 10-billion-bit array, to keep track
    of old values. Here are selected values of A005132.

    k     A005132[k]   A/k
--------- ---------- -------
        6         13 2.16667 
       34        113 3.32353 
      288       1090 3.78472 
     2422      10157 4.19364 
    23976     106218 4.43018 
   196643    1148360 5.83982 
  1708353   10411545 6.09449 
 16416785  101798991 6.20091 
138765002 1031389697 7.43264 
409493529 3454917187 8.43705 

    My little box has about 400Mb of memory, including swap space,
    so that's as far as I can go without extreme cleverness.

    I confirm Jud's statement: 1355 doesn't appear in the first 290
    million elements of A005132. (Nor in the first 409M, according to
    me.)
--
Don Reble       djr at nk.ca