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A073772
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Number of highly composite numbers (HCNs) between the n-th highly composite number k and 2*k if 2*k is a highly composite number, or -1 if 2*k is not a highly composite number.
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0
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0, 0, -1, 0, 0, 1, -1, -1, 0, 1, 1, -1, 0, -1, 1, 1, -1, 0, 1, 1, 1, -1, -1, 2, 2, -1, -1, 1, 1, 1, 2, -1, 2, 2, -1, -1, -1, 1, 1, 1, 2, -1, 2, 2, -1, 2, 2, 2, -1, -1, 2, -1, 2, -1, 2, 2, -1, 2, 2, 2, -1, -1, 2, 2, 2, -1, 2, 3, -1, -1, 2, 2, 2, -1, -1, 1, 1, 1, 1, -1, -1, 3, 3, 3, 3, -1, -1, 2, 2, 2, -1, 1, 1, -1, 3, 3, 3, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,24
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COMMENTS
| If 2*A002182(n) = A002182(m) then a(n) = m - n - 1; if 2*A002182(n) is not a highly composite number then a(n) = -1. The zero terms correspond to the terms of A072938, the negative terms correspond to the terms of A073771. The terms were determined by means of A. Flammenkamp's list (cf. Links).
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LINKS
| Achim Flammenkamp Highly Composite Numbers
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EXAMPLE
| a(3) = -1 since 4 is the third highly composite number and 2*4 = 8 is not a highly composite number; a(6) = 1 since 24 is the sixth highly composite number, 2*24 = 48 is the eighth highly composite number and the highly composite number 36 is between them; a(13) = 0 since 360 is the 13th highly composite number, 2*360 = 720 is the 14th highly composite number and there is no highly composite number between them.
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CROSSREFS
| Cf. A002182, A072938, A073771.
Sequence in context: A194606 A126389 A105551 * A164562 A058188 A070000
Adjacent sequences: A073769 A073770 A073771 * A073773 A073774 A073775
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KEYWORD
| sign
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 19 2002
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