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A022330
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Index of 3^n within sequence of numbers of form 2^i*3^j.
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4
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1, 3, 7, 12, 19, 27, 37, 49, 62, 77, 93, 111, 131, 152, 175, 199, 225, 252, 281, 312, 344, 378, 413, 450, 489, 529, 571, 614, 659, 705, 753, 803, 854, 907, 961, 1017, 1075, 1134, 1195, 1257, 1321, 1386, 1453, 1522, 1592, 1664, 1737, 1812, 1889, 1967, 2047, 2128
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(1000)=793775, a(10000)=79261054,
a(100000)=7924941755, a(1000000)=792482542841.
a(n) ~ 0.792*n^2 = ln(3)/ln(4)*n^2. More exact asymptotics? - Moshe Levin, Dec 22 2011
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LINKS
| Charles R Greathouse IV and Moshe Levin, Table of n, a(n) for n = 0..10000 Terms for n=0..1000 from Charles R Greathouse IV.
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FORMULA
| a(n) = A071521(A000244(n)); A003586(a(n)) = A000244(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 09 2006
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PROG
| (PARI) listsm(lim)=my(v=List(), N); for(n=0, log(lim)\log(3), N=3^n; while(N<=lim, listput(v, N); N<<=1)); v=Vec(v); vecsort(v)
list(lim)=my(v=listsm(3^floor(lim))); vector(floor(lim+1), i, setsearch(v, 3^(i-1))) \\ Charles R Greathouse IV, Aug 19 2011
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CROSSREFS
| Cf. A022331.
Sequence in context: A006317 A194147 A077043 * A024219 A025713 A022791
Adjacent sequences: A022327 A022328 A022329 * A022331 A022332 A022333
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KEYWORD
| nonn
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
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