Here's a generalized approach (not necessarily better, but convenient
if you need a variety of these kinds of sequences):
Alternating=: (1 :0)("0)
(+#) {. (, (altSeq/m)`:6)@]^:((#m) >.@%~ [)
)
altSeq=:4 :0
(, x`:6@{:)@(y`:6@{:)`''
)
Here's a couple examples:
9 +:`>: Alternating 1
1 2 4 5 10 11 22 23 46 47
9 ]`+:`>: Alternating 1
1 2 4 4 5 10 10 11 22 22
Note that (Alternating) is a parse time word. The phrase (+:`>:
Alternating) builds something that can be thought of as code, much
like a compiler builds code. But if you inspect this result you'll
see some differences from my original post.
+:`>: Alternating
((+ #) {. (, (, +:@{:)@(>:@{:))@]^:(2 >.@%~ [))"0
Can you think of why I might have introduced these complications? I
think that one of my changes is questionable and should perhaps be
removed or changed - do you have an idea of which change that would be
(and can you talk about why it should be changed)?
Thanks,
--
Raul
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