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A087306 a(n) is the start of the first arithmetic progression with common difference n of n numbers with the same prime signature. 2
1, 3, 155, 111, 3875983, 1333, 763274553951, 11978 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
First column of A087307; main diagonal of A114656.
a(7) > 29*10^9; a(8) = 11978.
a(n) > 10^10 for n from 9 to 11. a(12) = 120998. [From Donovan Johnson, Oct 24 2009]
LINKS
EXAMPLE
a(4) = 111 as 111, 115, 119 and 123 all are of the prime signature p*q.
CROSSREFS
Sequence in context: A075514 A344898 A327058 * A278877 A203682 A316479
KEYWORD
nonn,hard
AUTHOR
Amarnath Murthy, Sep 02 2003
EXTENSIONS
Edited and extended by David Wasserman, Jan 08 2006
a(7) from Donovan Johnson, Oct 24 2009
STATUS
approved

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Last modified April 14 05:31 EDT 2024. Contains 371655 sequences. (Running on oeis4.)