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Search: id:A080196
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| A080196 |
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13-smooth numbers which are not 11-smooth. |
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+0
4
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| 13, 26, 39, 52, 65, 78, 91, 104, 117, 130, 143, 156, 169, 182, 195, 208, 234, 260, 273, 286, 312, 325, 338, 351, 364, 390, 416, 429, 455, 468, 507, 520, 546, 572, 585, 624, 637, 650, 676, 702, 715, 728, 780, 819, 832, 845, 858, 910, 936, 975, 1001, 1014, 1040
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers of the form 2^r*3^s*5^t*7^u*11^v*13^w with r, s, t, u, v >= 0, w > 0.
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EXAMPLE
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78 = 2*3*13 is a term but 77 = 7*11 is not.
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PROGRAM
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(PARI) {m=1040; z=[]; for(r=0, floor(log(m)/log(2)), a=2^r; for(s=0, floor(log(m/a)/log(3)), b=a*3^s; for(t=0, floor(log(m/b)/log(5)), c=b*5^t; for(u=0, floor(log(m/c)/log(7)), d=c*7^u; for(v=0, floor(log(m/d)/log(11)), e=d*11^v; for(w=1, floor(log(m/e)/log(13)), z=concat(z, e*13^w))))))); z=vecsort(z); for(i=1, length(z), print1(z[i], ", "))}
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CROSSREFS
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Cf. A080197, A051038.
Sequence in context: A044898 A048842 A008595 this_sequence A033025 A044838 A033010
Adjacent sequences: A080193 A080194 A080195 this_sequence A080197 A080198 A080199
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KEYWORD
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easy,nonn
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AUTHOR
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Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Feb 10 2003
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