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Search: id:A072443
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| A072443 |
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Nonsquares which are the product of two numbers with the same digits (leading zeros are forbidden). |
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+0
3
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| 252, 403, 574, 736, 765, 976, 1008, 1207, 1300, 1458, 1462, 1612, 1729, 1855, 1944, 2268, 2296, 2430, 2668, 2701, 2944, 3154, 3478, 3627, 3640, 4032, 4275, 4606, 4930, 5092, 5605, 5848, 6624, 6786, 7663, 8722, 11110, 12240, 13390, 13552, 14560
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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P. Vaderlind, R. K. Guy and L. C. Larsen, The Inquisitive Problem Solver, Math. Assoc. Am., 2002, Problem P185.
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EXAMPLE
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12*21 = 252 = 12*21, 403 = 13*31, 574 = 14*41, etc
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PROGRAM
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(PARI) {for(n=100, 15000, k=floor(log(n)/log(100)); f=divisors(n); v=[]; for(h=1, matsize(f)[2], if(10^k<f[h]&&f[h]<10^(k+1), v=concat(v, f[h]))); b=matsize(v)[2]; if(b>1, w=[]; for(i=1, b, s=[]; a=v[i]; while(a>0, d=divrem(a, 10); a=d[1]; s=concat(d[2], s)); w=concat(w, [vecsort(s)])); c=0; for(i=1, b-1, for(j=i+1, b, if(c<1&&w[i]==w[j], if(v[i]*v[j]==n, print1(n, ", "); c=1))))))}
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CROSSREFS
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A076750 and A077760 are subsequences.
Sequence in context: A046331 A066695 A104396 this_sequence A129623 A062904 A032800
Adjacent sequences: A072440 A072441 A072442 this_sequence A072444 A072445 A072446
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KEYWORD
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base,nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Nov 11 2002
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EXTENSIONS
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Extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 12 2002
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