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.

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

1,2

Comments

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

Links

Table of n, a(n) for n=1..67.

Example

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).

Sequence in context: A113350 A227372 A359131 * A164679 A275183 A275131

Adjacent sequences: A164675 A164676 A164677 * A164679 A164680 A164681

Keyword

nonn,tabl,uned

Author

Alford Arnold, Aug 25 2009

Status

approved