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Search: id:A126254
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| A126254 |
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Number of distinct terms i^j for 1 <= i,j <= n. |
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+0
4
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| 1, 3, 7, 11, 19, 28, 40, 50, 60, 76, 96, 115, 139, 163, 189, 207, 239, 270, 306, 340, 378, 417, 461, 503, 539, 585, 621, 670, 726, 779, 839, 881, 941, 1003, 1067, 1113, 1185, 1254, 1326, 1397, 1477, 1553, 1637, 1717, 1799, 1884, 1976, 2063, 2135, 2225
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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An easy upper bound is n(n-1)+1 = A002061(n).
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LINKS
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N. Hobson, Table of n, a(n) for n = 1..1000
N. Hobson, Home page (listed in lieu of email address)
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EXAMPLE
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a(4) = 11, as there are 11 distinct terms in 1^1=1, 1^2=1, 1^3=1, 1^4=1, 2^1=2, 2^2=4, 2^3=8, 2^4=16, 3^1=3, 3^2=9, 3^3=27, 3^4=81, 4^1=4, 4^2=16, 4^3=64, 4^4=256.
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PROGRAM
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(PARI) lim=50; z=listcreate(lim*(lim-1)+1); for(m=1, lim, for(i=1, m,
x=factor(i); x[, 2]*=m; s=Str(x); f=setsearch(z, s, 1); if(f,
listinsert(z, s, f))); t=factor(m); for(j=1, m, x=t; x[, 2]=j*t[, 2];
s=Str(x); f=setsearch(z, s, 1); if(f, listinsert(z, s, f))); print1(#z, ", "))
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CROSSREFS
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Cf. A027424, A061786, A126255-A126257.
Sequence in context: A105888 A098379 A049754 this_sequence A092102 A123080 A022406
Adjacent sequences: A126251 A126252 A126253 this_sequence A126255 A126256 A126257
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KEYWORD
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easy,nonn
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AUTHOR
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Nick Hobson Dec 24 2006
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