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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
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
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