A164738 Triangle read by rows. Row 0 = {2}; left half of row n+1 = row n, right half = row n reversed with each term replaced by the next prime.

2, 2, 3, 2, 3, 5, 3, 2, 3, 5, 3, 5, 7, 5, 3, 2, 3, 5, 3, 5, 7, 5, 3, 5, 7, 11, 7, 5, 7, 5, 3, 2, 3, 5, 3, 5, 7, 5, 3, 5, 7, 11, 7, 5, 7, 5, 3, 5, 7, 11, 7, 11, 13, 11, 7, 5, 7, 11, 7, 5, 7, 5, 3, 2, 3, 5, 3, 5, 7, 5, 3, 5, 7, 11, 7, 5, 7, 5, 3, 5, 7, 11, 7, 11, 13, 11, 7, 5, 7, 11, 7, 5, 7, 5, 3, 5, 7, 11, 7

Offset

0,1

Comments

Row n has 2^n terms.

Row sums = (2, 5, 13, 33, 83, 205, 495,...) = A007443, the binomial transform of the primes.

Links

Alois P. Heinz, Rows n = 0..13, flattened

Example

The triangle begins:
  2;
  2, 3;
  2, 3, 5, 3;
  2, 3, 5, 3, 5, 7, 5, 3;
  2, 3, 5, 3, 5, 7, 5, 3, 5, 7, 11, 7, 5, 7, 5, 3;
  ...

Mathematica

Flatten[NestList[Join[ #, NextPrime[Reverse[ # ]]] &, {2}, 7]] (* Zak Seidov, Aug 24 2009 *)

Crossrefs

Cf. A000040, A007443, A088696.

Sequence in context: A169614 A037126 A080092 * A126225 A306997 A056160

Adjacent sequences: A164735 A164736 A164737 * A164739 A164740 A164741

Keyword

nonn,tabf

Author

Gary W. Adamson, Aug 23 2009

Extensions

More terms from Zak Seidov, Aug 24 2009

Edited by Zak Seidov and N. J. A. Sloane, Aug 25 2009

Offset 0 from Alois P. Heinz, Oct 31 2023

Status

approved