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A080287 Successively larger gaps in Ulam numbers start at this Ulam number. 4
1, 4, 8, 18, 38, 87, 114, 155, 282, 751, 949, 1257, 1553, 1858, 2178, 4800, 5384, 18796, 37562, 64420, 252719, 933709, 289738117, 332250401, 667752899, 699497052, 966290117, 224582902442, 319654121875, 418843012121, 802386465583 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The gaps are in A080288.
REFERENCES
D. E. Knuth, The Art of Computer Programming, vol 4A, section 7.1.3, exercise 141.
LINKS
Philip Gibbs, Judson McCranie, The Ulam Numbers up to One Trillion, (2017).
EXAMPLE
87 and 97 are successive Ulam numbers and this is the first gap of 10 or larger, so 87 is in the sequence.
CROSSREFS
Sequence in context: A190062 A228231 A175657 * A280155 A075310 A075797
KEYWORD
nonn,more,hard
AUTHOR
Jud McCranie, Feb 12 2003
EXTENSIONS
Added a(23) found by Don Knuth - Jud McCranie, Aug 22 2008
a(24) on Feb 29 2012; a(25) on Jul 20 2012; and a(26) on Jul 24 2012 by Jud McCranie
a(27) found by Philip Gibbs, Sep 02 2015
a(28) found by Philip Gibbs and Jud McCranie, Sep 09 2015
a(29)-a(31) found by Philip Gibbs, Oct 2017
Missing term a(23) added by Jud McCranie, Oct 27 2017
STATUS
approved

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Last modified April 22 02:54 EDT 2024. Contains 371887 sequences. (Running on oeis4.)