cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A108575 Numbers k such that the continued fraction for sqrt(k) is multiplicative.

Original entry on oeis.org

3, 7, 8, 13, 14, 15, 22, 23, 24, 32, 33, 34, 35, 44, 47, 48, 58, 59, 60, 62, 63, 74, 75, 78, 79, 80, 95, 96, 98, 99, 114, 119, 120, 135, 136, 138, 140, 141, 142, 143, 160, 162, 164, 167, 168, 185, 187, 189, 192, 194, 195, 215, 219, 220, 222, 223, 224, 248, 252, 254
Offset: 1

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Author

David W. Wilson, Jun 10 2005

Keywords

Comments

m^2 - m < a(n) < m^2 for some m.

Examples

			The continued fraction for sqrt(7) is c = (2, 1, 1, 1, 4, 1, 1, 1, 4, ...) = A010121. If we index starting at 0, so that c(0) = 2, c is multiplicative (the value at c(0) is immaterial). Hence 7 is in the sequence.

Crossrefs

Cf. A010121, A109054 (with squares included).

A109150 Numbers k such that the continued fraction sequence of sqrt(k) is not multiplicative.

Original entry on oeis.org

2, 5, 6, 10, 11, 12, 17, 18, 19, 20, 21, 26, 27, 28, 29, 30, 31, 37, 38, 39, 40, 41, 42, 43, 45, 46, 50, 51, 52, 53, 54, 55, 56, 57, 61, 65, 66, 67, 68, 69, 70, 71, 72, 73, 76, 77, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 97, 101, 102, 103, 104, 105, 106, 107
Offset: 1

Views

Author

Mitch Harris, Jun 20 2005

Keywords

Examples

			The continued fraction of sqrt(21) is (4; 1, 1, 2, 1, 1, 8, ...) = A010125, which is not multiplicative since c(2) = 1, c(3) = 2, but c(6) = 8.

Crossrefs

Complement of A109054.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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