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.

A164678 Convolve A008619 with sequences which map to 2,3,5,7,11,13,17... A000040 then, by bending when needed, summarize the results in a triangular array.

Original entry on oeis.org

1, 2, 1, 5, 4, 2, 9, 8, 6, 2, 17, 16, 14, 9, 3, 28, 27, 25, 20, 12, 3, 47, 46, 44, 39, 30, 16, 4, 73, 72, 70, 65, 56, 40, 20, 4, 114, 113, 111, 106, 97, 80, 55, 25, 5, 170, 169, 167, 162, 153, 136, 109, 70, 30, 5, 253, 252, 250, 245, 236, 219, 191, 147, 91, 36, 6, 365
Offset: 1

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Author

Alford Arnold, Aug 25 2009

Keywords

Comments

Sequence A164680 is not in the triangle since 45 = 3*15 and 15 is not a member of A000040 (the prime numbers).

Examples

			The desired triangle begins:
.1
.2..1
.5..4..2
.9..8..6..2
17.16.14..9..3
28.27.25.20.12..3
47.46.44.39.30.16..4
etc.
Note that 21 = 3*7 maps to 1,2,5,9,17,27,44,... A139672 is embedded in the triangle.
		

Crossrefs

Cf. A008619 A002620 A006918 A097701 A139672 ... A000097 (embedded sequences).