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Search: id:A062398
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| A062398 |
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Numbers such that the product of the digits and the sum of the digits are squares. |
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+0
1
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| 1, 4, 9, 10, 22, 40, 88, 90, 100, 103, 108, 130, 144, 180, 202, 207, 220, 270, 301, 306, 310, 360, 400, 405, 414, 441, 450, 466, 504, 540, 603, 630, 646, 664, 702, 709, 720, 790, 801, 808, 810, 880, 889, 898, 900, 907, 970, 988, 1000, 1003, 1008, 1012, 1017
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
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144 belongs to the sequence as sum of digits = 9 and the product of the digits = 16.
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PROGRAM
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(PARI) SumD(x)= { s=0; while (x>9, s+=x-10*(x\10); x\=10); return(s + x) } ProdD(x)= { p=1; while (x>9, p*=(x-10*(x\10)); x\=10); return(p*x) } { n=0; for (m=1, 10^9, if (issquare(ProdD(m)) && issquare(SumD(m)), write("b062398.txt", n++, " ", m); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 07 2009]
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CROSSREFS
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Cf. A062397.
Sequence in context: A109412 A061766 A109448 this_sequence A030754 A077584 A093896
Adjacent sequences: A062395 A062396 A062397 this_sequence A062399 A062400 A062401
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KEYWORD
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nonn,base,easy
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 28 2001
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EXTENSIONS
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Corrected and extended by Erich Friedman (efriedma(AT)stetson.edu), Jul 02 2001
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