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Search: id:A130688
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| A130688 |
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Numbers n with following property: suppose n^6 = d1 d2 d3 ...dk in decimal; then d1! + d2! + ... + dk! is a square. |
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+0
1
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| 1, 6, 747, 2802, 10000, 10256, 11876, 13875, 14623, 14710, 17117, 18090, 23919, 26569, 34282, 35402, 40515, 41202, 41850, 42195, 44684, 48396, 54698, 58509, 59293, 59644, 59900, 65502, 67795, 74004, 75320, 79593, 82677, 82713, 83402
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Numbers n such that n^6 is in A130687.
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EXAMPLE
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a(2)=6
6^6=46656
(4!+6!+6!+5!+6!)^(1/2)=48 is an integer
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MAPLE
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A061602 := proc(n) local digs ; digs := convert(n, base, 10) ; add(factorial(op(i, digs)), i=1..nops(digs)) ; end: isA130687 := proc(n) RETURN(issqr(A061602(n))) ; end: isA130688 := proc(n) RETURN(isA130687(n^6)) ; end: for n from 1 to 130000 do if isA130688(n) then printf("%d, ", n) ; fi : od:
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PROGRAM
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(PARI) for(n=1, 10^5, m=n^6; s=0; while(m, s+=(m%10)!; m\=10); if(issquare(s), print1(n", ")))
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CROSSREFS
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Cf. A130687, A089185, A126076, A126077, A126078.
Adjacent sequences: A130685 A130686 A130687 this_sequence A130689 A130690 A130691
Sequence in context: A052295 A080369 A036981 this_sequence A088217 A020542 A045480
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KEYWORD
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nonn
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AUTHOR
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Aktar Yalcin (aktaryalcin(AT)msn.com), Jun 30 2007
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EXTENSIONS
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Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl) and Martin Fuller (martin_n_fuller(AT)btinternet.com), Jul 13 2007
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