A086887 a(n) = least semiprime with factors not previously used containing integers 2n and 2n+1 as substrings.

1111, 6, 205, 427, 1577, 11639, 1651, 22499, 2771, 34571, 253411, 5129, 60491, 59701, 8149, 9517, 307793, 122491, 13579, 53237, 168019, 18103, 202451, 21667, 169963, 377753, 27613, 301337, 88391, 34633, 368413, 750523, 418573, 44287

Offset

0,1

Links

Table of n, a(n) for n=0..33.

Example

Sequence:....1111....6...205...427...1577....11639....1651..
Factors.:..101*11..2*3..41*5..61*7..83*19..103*113..127*13..
2n, 2n+1:.....0,1..2,3...4,5...6,7....8,9....10,11...12,13..
n ......:.......0....1.....2.....3......4........5.......6..

Crossrefs

Sequence in context: A287283 A277927 A367814 * A278870 A278898 A278915

Adjacent sequences: A086884 A086885 A086886 * A086888 A086889 A086890

Keyword

base,easy,nonn

Author

Jason Earls, Aug 22 2003

Extensions

More terms from Ray Chandler, Aug 31 2003

Status

approved