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A176146
a(n) = n-th-semiprime without last digit.
0
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]
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Giovanni Teofilatto, Apr 10 2010
STATUS
approved