

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
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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

Table of n, a(n) for n=1..31.
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

Cf. A002858, A080288, A214603, A274522.
Sequence in context: A190062 A228231 A175657 * A280155 A075310 A075797
Adjacent sequences: A080284 A080285 A080286 * A080288 A080289 A080290


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



