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 A181988 If n is odd, a(n) = (n+1)/2; if n is even, a(n) = a(n/2) + A003602(n). 4
 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, 16, 16, 6, 17, 18, 18, 15, 19, 20, 20, 12, 21, 22, 22, 18, 23, 24, 24, 10, 25, 26, 26, 21, 27, 28, 28, 16, 29, 30, 30, 24, 31, 32, 32, 7, 33, 34, 34, 27, 35, 36 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The original definition was "Interleaved multiples of the positive integers". This sequence is A_1 where A_k = Interleave(k*counting,A_(k+1)). 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 LINKS Antti Karttunen, Table of n, a(n) for n = 1..8191 FORMULA a((2*n-1)*2^p) = n*(p+1), p >= 0. a(n) = A001511(n)*A003602(n). - L. Edson Jeffery, Nov 21 2015. (Follows directly from above formula.) - Antti Karttunen, Jan 19 2016 MAPLE nmax:=70: for p from 0 to ceil(simplify(log(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 PROG (Haskell) interleave (hdx : tlx) y = hdx : interleave y tlx oeis003602 = interleave [1..] oeis003602 oeis181988 = interleave [1..] (zipWith (+) oeis003602 oeis181988) (Python) from itertools import count def interleave(A):     A1=next(A)     A2=interleave(A)     while True:         yield next(A1)         yield next(A2) def multiples(k):     return (k*i for i in count(1)) interleave(multiples(k) for k in count(1)) (Scheme, with memoization-macro definec) (definec (A181988 n) (if (even? n) (+ (A003602 n) (A181988 (/ n 2))) (A003602 n))) ;; Antti Karttunen, Jan 19 2016 CROSSREFS Cf. A220466. Cf. A001511, A003602. Sequence in context: A134482 A132921 A255232 * A194173 A028825 A132924 Adjacent sequences:  A181985 A181986 A181987 * A181989 A181990 A181991 KEYWORD easy,nonn AUTHOR David Spies, Apr 04 2012 EXTENSIONS Definition replaced by a formula provided by David Spies, Sep 17 2012.  N. J. A. Sloane, Nov 22 2015 STATUS approved

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Last modified May 25 15:24 EDT 2019. Contains 323572 sequences. (Running on oeis4.)