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A323645
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a(n) is the number of visible faces in the perspective view of the stepped pyramid with n levels described in A245092.
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1
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3, 6, 12, 17, 21, 28, 32, 39, 46, 56, 60, 69, 73, 81, 92, 103, 107, 118, 122
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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The shape of the n-th level of the pyramid allows us to know if n is prime (see the Formula section).
For more sequences that we can find in the pyramid see A262626.
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LINKS
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FORMULA
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a(n) = a(n-1) + 4 iff n is a prime > 3 (A215848).
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CROSSREFS
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Cf. A000040, A000203, A024916, A196020, A215848, A224880, A235791, A236104, A237048, A237270, A237271, A237593, A245092, A262626, A299692 (total area).
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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