A080287 Successively larger gaps in Ulam numbers start at this Ulam number.

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

Author

Jud McCranie, Feb 12 2003

Keywords

• nonn
• more
• hard

Comments

The gaps are in A080288.

Examples

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

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).

Crossrefs

Cf. A002858, A080288, A214603, A274522.

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 27 2017

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