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Search: id:A068786
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| A068786 |
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S(n; 1,0) = S(n; 3,0) where S(n; t,s) is the number of length n 4-ary strings whose digits sum to t mod 4 and whose sum of products of all pairs of digits sum to s mod 4. |
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10
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OFFSET
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1,2
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LINKS
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F. Ruskey, 4-ary strings with given trace and subtrace.
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FORMULA
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S(n; t, s) = S(n-1; t, s) + S(n-1; t+3, s+3t+1) + S(n-1; t+2, s+2t) + S(n-1; t+1, s+t+1)
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CROSSREFS
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Cf. A073953, A068711, A073955, A068777, A068778, A073959, A068788, A068789, A073962.
Sequence in context: A111281 A018021 A074405 this_sequence A102699 A025169 A111282
Adjacent sequences: A068783 A068784 A068785 this_sequence A068787 A068788 A068789
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KEYWORD
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nonn
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AUTHOR
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Frank Ruskey (fruskey(AT)cs.uvic.ca), Mar 29 2002
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