A176146 a(n) = n-th-semiprime without last digit.

0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 14, 14, 14, 14, 14, 15, 15, 15, 16, 16, 16, 17, 17, 18, 18, 18, 19, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 22, 22, 23, 23, 24, 24, 25

Offset

1,7

Comments

Sequence A131109 shows that a(n+1)-a(n) can be larger than 1. [From T. D. Noe, Apr 12 2010]

The differences exceed 1 for the first time between a(186) = 59 and a(187) = 61. [R. J. Mathar, Apr 12 2010]

Links

Table of n, a(n) for n=1..81.

Crossrefs

Cf. A176044, A001358, A106146.

Sequence in context: A289133 A367194 A135297 * A171481 A230775 A108037

Adjacent sequences: A176143 A176144 A176145 * A176147 A176148 A176149

Keyword

base,easy,nonn

Author

Giovanni Teofilatto, Apr 10 2010

Status

approved