%I #45 Jul 12 2022 09:50:04
%S 1,2,2,3,3,4,4,4,5,6,6,6,7,8,8,5,9,10,10,9,11,12,12,8,13,14,14,12,15,
%T 16,16,6,17,18,18,15,19,20,20,12,21,22,22,18,23,24,24,10,25,26,26,21,
%U 27,28,28,16,29,30,30,24,31,32,32,7,33,34,34,27,35,36
%N If n is odd, a(n) = (n+1)/2; if n is even, a(n) = a(n/2) + A003602(n).
%C The original definition was "Interleaved multiples of the positive integers".
%C This sequence is A_1 where A_k = Interleave(k*counting,A_(k+1)).
%C Show your friends the first 15 terms and see if they can guess term number 16. (If you want to be fair, you might want to show them A003602 first.) - _David Spies_, Sep 17 2012
%H Antti Karttunen, <a href="/A181988/b181988.txt">Table of n, a(n) for n = 1..8191</a>
%F a((2*n-1)*2^p) = n*(p+1), p >= 0.
%F a(n) = A001511(n)*A003602(n). - _L. Edson Jeffery_, Nov 21 2015. (Follows directly from above formula.) - _Antti Karttunen_, Jan 19 2016
%p nmax:=70: for p from 0 to ceil(simplify(log[2](nmax))) do for n from 1 to ceil(nmax/(p+2)) do a((2*n-1)*2^p) := n*(p+1) od: od: seq(a(n), n=1..nmax); # _Johannes W. Meijer_, Jan 21 2013
%o (Haskell)
%o interleave (hdx : tlx) y = hdx : interleave y tlx
%o oeis003602 = interleave [1..] oeis003602
%o oeis181988 = interleave [1..] (zipWith (+) oeis003602 oeis181988)
%o (Python)
%o from itertools import count
%o def interleave(A):
%o A1=next(A)
%o A2=interleave(A)
%o while True:
%o yield next(A1)
%o yield next(A2)
%o def multiples(k):
%o return (k*i for i in count(1))
%o interleave(multiples(k) for k in count(1))
%o (Python)
%o def A181988(n): return (m:=(n&-n).bit_length())*((n>>m)+1) # _Chai Wah Wu_, Jul 12 2022
%o (Scheme, with memoization-macro definec)
%o (definec (A181988 n) (if (even? n) (+ (A003602 n) (A181988 (/ n 2))) (A003602 n)))
%o ;; _Antti Karttunen_, Jan 19 2016
%Y Cf. A220466.
%Y Cf. A001511, A003602.
%K easy,nonn
%O 1,2
%A _David Spies_, Apr 04 2012
%E Definition replaced by a formula provided by _David Spies_, Sep 17 2012. _N. J. A. Sloane_, Nov 22 2015
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