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A178961
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Partial sums of number of symmetric foldings of a strip of n stamps (A001010).
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0
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1, 3, 5, 9, 15, 23, 41, 61, 117, 165, 343, 475, 1049, 1397, 3267, 4275, 10419, 13231, 33545, 41965, 109499, 133895, 359367, 434123, 1189795, 1412351, 3952757, 4646449, 13211071, 15318819, 44260077, 50916453, 148927917, 169476849
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OFFSET
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1,2
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COMMENTS
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Number of symmetric foldings of a strip of <= n stamps. The subsequence of primes begins 3, 5, 23, 41, 61, 1049, 1412351.
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LINKS
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FORMULA
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EXAMPLE
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a(13) = 1 + 2 + 2 + 4 + 6 + 8 + 18 + 20 + 56 + 48 + 178 + 132 + 574 = 1049 is prime.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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