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A068789
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S(n; 2,0) 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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9
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OFFSET
| 1,2
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LINKS
| F. Ruskey, 4-ary strings with given trace and subtrace.
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FORMULA
| 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
| Cf. A073953, A068711, A073955, A068777, A068786, A068778, A073959, A068788, A073962.
Sequence in context: A005388 A053503 A153957 * A009624 A009161 A009290
Adjacent sequences: A068786 A068787 A068788 * A068790 A068791 A068792
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KEYWORD
| nonn,base
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AUTHOR
| Frank Ruskey (ruskey(AT)cs.uvic.ca), Mar 29 2002
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