September 27, 2016: refactoring and sync
In [64]:
%run "../src/start_session.py"
%run "../src/recurrences.py"
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import oeis
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s = oeis.oeis_search(id=48993)
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s()
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from sympy.functions.combinatorial.numbers import stirling
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s = IndexedBase('s')
n, k = symbols('n k')
stirling_recurrence_spec = recurrence_spec(recurrence_eq=Eq(s[n+1, k+1], s[n, k] + (k+1)*s[n, k+1]),
recurrence_symbol=s,
variables=[n,k])
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stirling_recurrence_spec
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unfolded = stirling_recurrence_spec.unfold(depth=1)
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unfolded
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instantiated = unfolded.instantiate(strategy=raw(substitutions={n:9,k:4}))
instantiated
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known_binomials = {s[n,k]:stirling(n,k) for n in [10,9,8] for k in range(2,6)}
checked = instantiated.instantiate(strategy=raw(substitutions=known_binomials))
checked
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In [59]:
checked.subsume()
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In [82]:
based_recurrence_spec = unfolded.instantiate(strategy=based(arity=doubly_indexed()))
based_recurrence_spec
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based_recurrence_spec.subsume()
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In [66]:
ipython_latex_description(rec_spec=stirling_recurrence_spec, depths=range(9), based_instantiation=False,
arity=doubly_indexed())
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In [36]:
s = oeis.oeis_search(seq=[1,1,4,3,1,27,19,6,1,256,175,55,10,1])
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s()
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In [40]:
s = oeis.oeis_search(id=264428)
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s()
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