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 A147610 a(n) = 3^{wt(n-1)-1}, where wt() = A000120(). 15
 1, 1, 3, 1, 3, 3, 9, 1, 3, 3, 9, 3, 9, 9, 27, 1, 3, 3, 9, 3, 9, 9, 27, 3, 9, 9, 27, 9, 27, 27, 81, 1, 3, 3, 9, 3, 9, 9, 27, 3, 9, 9, 27, 9, 27, 27, 81, 3, 9, 9, 27, 9, 27, 27, 81, 9, 27, 27, 81, 27, 81, 81, 243, 1, 3, 3, 9, 3, 9, 9, 27, 3, 9, 9, 27, 9, 27, 27, 81, 3, 9, 9, 27, 9, 27, 27, 81, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,3 COMMENTS a(n) = A147582(n)/4. LINKS Omar E. Pol, Illustration of initial terms (Overlapping squares) [From Omar E. Pol, Nov 15 2009] FORMULA a(n) = 3^A048881(n-2). - R. J. Mathar, Apr 30 2009 Recurrence: Write n = 2^i + 1 + j, 0 <= j < 2^i. Then a(2^i+1) = 1; for j>0, a(2^i+j+1) = 3*a(j+1). - N. J. A. Sloane, Jun 09 2009 G.f.: x*(Product_{k>=0} (1 + 3*x^(2^k)) - 1)/3. - N. J. A. Sloane, Jun 10 2009 EXAMPLE When written as a triangle: .1, .1,3, .1,3,3,9, .1,3,3,9,3,9,9,27, .1,3,3,9,3,9,9,27,3,9,9,27,9,27,27,81, .1,3,3,9,3,9,9,27,3,9,9,27,9,27,27,81,3,9,9,27,9,27,27,81,9,27,27,81,27,81,81,243, .... Rows converge to A048883. Row sums give A000302. Partial sums give A151920. MAPLE A000120 := proc(n) local a, d; a := 0 ; for d from 0 to ilog2(n) do a := a+ ( floor(n/2^d) mod 2) ; od: a ; end: A048881 := proc(n) A000120(n+1)-1 ; end: A147610 := proc(n) 3^A048881(n) ; end: seq(A147610(n), n=0..100) ; # R. J. Mathar, Apr 30 2009 CROSSREFS Cf. A048883, A000120, A000302, A151920, A147582, A048881. Cf. A079314. - Omar E. Pol, Nov 15 2009 Sequence in context: A327190 A160123 A238784 * A238313 A163270 A098743 Adjacent sequences:  A147607 A147608 A147609 * A147611 A147612 A147613 KEYWORD nonn AUTHOR N. J. A. Sloane, Apr 29 2009 EXTENSIONS Extended by R. J. Mathar, Apr 30 2009 Offset corrected by N. J. A. Sloane, Jun 09 2009 Further edited by N. J. A. Sloane, Aug 06 2009 STATUS approved

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Last modified October 19 04:40 EDT 2019. Contains 328211 sequences. (Running on oeis4.)