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A110921
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Numbers n such that n = R(digit_sum(n)) where R is the digit reversal and digit_sum is the digital sum.
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1
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OFFSET
| 1,2
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REFERENCES
| Tricky Number, Science Illustrated, Jan/Feb 2009, p. 80. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 20 2008]
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LINKS
| Masahiko Fujiwara, Title?.
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FORMULA
| k such that A007953(k)*A004086(A007953(k)) = k. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 20 2008]
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EXAMPLE
| Example: n = 1729: s = 1+7+2+9=19, 19*91=1729.
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PROG
| #!/usr/bin/perl -w use strict; my $i; my $j; for $i ( 1e0 .. 1e6 ) { my $sum = 0; my $rev = 0; for $j ( 1 .. length ( $i ) ) { $sum += substr ( $i, $j - 1, 1 ); } $rev = reverse $sum; print "$i " if $sum * $rev == $i; }
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CROSSREFS
| Cf. A004086, A007953. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 20 2008]
Sequence in context: A016768 A059977 A116205 * A203650 A096302 A107914
Adjacent sequences: A110918 A110919 A110920 * A110922 A110923 A110924
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KEYWORD
| fini,full,nonn,base
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AUTHOR
| Michael Vang (michael.vang(AT)gmail.com), Sep 22 2005
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EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Jan 15 2009, at the suggestion of Klaus Brockhaus
Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Aug 03 2010
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