Talk:Recamán's sequence

Mistake in Recaman's sequence?

The description of A005132 sounds, as if there were do double items.
But the list shows that a(20) = a(24) = 42. What's wrong?

And what's a good place to ask questions like this, if it's not here? Tilman Piesk 23:51, 11 September 2011 (UTC)

The right place would be on the pink box comments for A5132. But the sequence needs to have pending edits for you to be able to make pink box comments, so I've done a rather routine edit of the kind that would have taken place sooner or later anyway. Alonso del Arte 00:22, 12 September 2011 (UTC)

Ok. The sequence "tries" to avoid repeats, but isn't always successful.

Maybe that should be mentioned explicitly in the description. Tilman Piesk 09:08, 12 September 2011 (UTC)

Warned by your comment here the 42=18+24 side effect of 18-24<0 was obvious for me. Maybe edit the sequence and use 42 in examples to make it obvious also for others. –Frank Ellermann 07:55, 13 September 2011 (UTC)

I created the stub page Recamán's sequence (and the Recaman's sequence redirect, without the accent on the á.) You may want to move the discussion on Talk:Recamán's sequence, do you want me to do it? — Daniel Forgues 17:45, 13 September 2011 (UTC)

Good idea, it's not really about the main page. –Frank Ellermann 10:38, 16 September 2011 (UTC)

The "not already in the sequence" only applies to the subtraction case, not to the addition case. — Daniel Forgues 16:04, 30 August 2018 (EDT)

A possible third sequence: “take root if possible, otherwise take power”?

A possible third sequence: “take root if possible, otherwise take power”?

a (1) = 2; a (n) = n √  a (n  −  1)

if

a (n  −  1)

is an

n

th power, otherwise

a (n) = (a (n  −  1))  n

.

{2, 4, 64, 16777216, 1329227995784915872903807060280344576, 1048576, 1393796574908163946345982392040522594123776, ...}

a(8) = 14242792383964888162918480513432465216409371640403009729971037612045113415478719007639881209041451055630074000655093473974722206675223109929434400259100512062680086347153555148539548552831624261944567042435944993535084132588196941322891072406503377213352323037077384970994853089450777507879083442634420291861180736024127002634265953304576

I’m afraid it can only trivially grow... — Daniel Forgues 16:02, 30 August 2018 (EDT) Correction:

n

th root or

n

th power. — Daniel Forgues 22:51, 30 August 2018 (EDT)

No, it doesn’t,

a (5)

is a 6^th power! So the sequence is not trivial! — Daniel Forgues 22:51, 30 August 2018 (EDT)