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Search: id:A078395
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| A078395 |
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a(1) = 1, a(n) for n > 1 is the smallest multiple of a(n-1) that begins with the reverse concatenation from n to 1. |
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4
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| 1, 21, 3213, 4321485, 5432106645, 6543211466594880, 76543214032699698271680, 8765432112983964669342594296640, 9876543213798659527816605720220081111680
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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For n = 3 we have a(n-1) = a(2) = 21; 153*21 = 3213 is the smallest multiple of a(2) that begins with 321, so a(3) = 3213.
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PROGRAM
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(PARI) {print1(a=1, ", "); for(n=2, 9, k=floor(log(a)/log(10))+1; v=Str(1); for(i=2, n, v=concat(Str(i), v)); s=eval(v); t=s+1; m=floor(log(s)/log(10))+1; d=k-m; s=s*10^d; t=t*10^d; b=1; j=d; while(b>0, q=floor(s/a); while(b>0&&(p=q*a)<t, if(p>=s, print1(p, ", "); b=0, q++)); s=10*s; t=10*t); a=p)}
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CROSSREFS
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Cf. A078296, A078396, A078397.
Sequence in context: A095154 A018238 A098724 this_sequence A153833 A055416 A074053
Adjacent sequences: A078392 A078393 A078394 this_sequence A078396 A078397 A078398
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 26 2002
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EXTENSIONS
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Edited and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Dec 06 2002
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