A071819 a(n) is the difference between the two smallest positive integers that you cannot obtain using the integers {1,2,...,n} at most once and the four operators +, -, *, /.

1, 1, 1, 2, 3, 23, 5, 144, 98, 658

Offset

1,4

Links

Table of n, a(n) for n=1..10.

Gilles Bannay, Countdown Problem

Index entries for similar sequences

Example

a(4)=2 because 29 and 31 are the smallest numbers that you cannot obtain using {1,2,3,4} and the four operations and 31-29 = 2.

Crossrefs

Cf. A060315.

Sequence in context: A114101 A114007 A282795 * A329916 A085946 A280894

Adjacent sequences: A071816 A071817 A071818 * A071820 A071821 A071822

Keyword

hard,more,nonn

Author

Koksal Karakus (karakusk(AT)hotmail.com), Jun 07 2002

Status

approved