A080287 - OEIS

%I #67 Mar 28 2018 22:02:51

%S 1,4,8,18,38,87,114,155,282,751,949,1257,1553,1858,2178,4800,5384,

%T 18796,37562,64420,252719,933709,289738117,332250401,667752899,

%U 699497052,966290117,224582902442,319654121875,418843012121,802386465583

%N Successively larger gaps in Ulam numbers start at this Ulam number.

%C The gaps are in A080288.

%D D. E. Knuth, The Art of Computer Programming, vol 4A, section 7.1.3, exercise 141.

%H Philip Gibbs, Judson McCranie, <a href="https://www.researchgate.net/profile/Philip_Gibbs/publication/320980165_The_Ulam_Numbers_up_to_One_Trillion/links/5a058786aca2726b4c78588d/The-Ulam-Numbers-up-to-One-Trillion.pdf">The Ulam Numbers up to One Trillion</a>, (2017).

%e 87 and 97 are successive Ulam numbers and this is the first gap of 10 or larger, so 87 is in the sequence.

%Y Cf. A002858, A080288, A214603, A274522.

%K nonn,more,hard

%O 1,2

%A _Jud McCranie_, Feb 12 2003

%E Added a(23) found by _Don Knuth_ - _Jud McCranie_, Aug 22 2008

%E a(24) on Feb 29 2012; a(25) on Jul 20 2012; and a(26) on Jul 24 2012 by _Jud McCranie_

%E a(27) found by Philip Gibbs, Sep 02 2015

%E a(28) found by Philip Gibbs and _Jud McCranie_, Sep 09 2015

%E a(29)-a(31) found by Philip Gibbs, Oct 2017

%E Missing term a(23) added by Jud McCranie, Oct 27 2017