A395094 Irregular table T(n, k), n > 0, k = 1..A395087(n), read by rows; the n-th row lists (in ascending order) the X-coordinates of the vertices of the convex hull of the finite point set {(k, prime(k)), k = 1..n} (where prime(k) denotes the k-th prime number).

1, 1, 2, 1, 2, 3, 1, 2, 4, 1, 2, 4, 5, 1, 2, 4, 5, 6, 1, 2, 4, 6, 7, 1, 2, 4, 7, 8, 1, 2, 4, 8, 9, 1, 2, 4, 8, 9, 10, 1, 2, 4, 8, 10, 11, 1, 2, 4, 8, 11, 12, 1, 2, 4, 8, 11, 13, 1, 2, 4, 8, 13, 14, 1, 2, 4, 8, 13, 15, 1, 2, 4, 8, 15, 16, 1, 2, 4, 8, 15, 17

Offset

1,3

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10008 (rows for n = 1..597 flattened)

Rémy Sigrist, PARI program

Formula

T(n, 1) = 1.

T(n, A395087(n)) = n.

Example

Table T(n, k) begins:
  n   n-th row
  --  -------------------
   1  1
   2  1, 2
   3  1, 2, 3
   4  1, 2, 4
   5  1, 2, 4, 5
   6  1, 2, 4, 5, 6
   7  1, 2, 4, 6, 7
   8  1, 2, 4, 7, 8
   9  1, 2, 4, 8, 9
  10  1, 2, 4, 8, 9, 10
  11  1, 2, 4, 8, 10, 11
  12  1, 2, 4, 8, 11, 12
  13  1, 2, 4, 8, 11, 13
  14  1, 2, 4, 8, 13, 14
  15  1, 2, 4, 8, 13, 15
  16  1, 2, 4, 8, 15, 16
  17  1, 2, 4, 8, 15, 17

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A246033, A395087, A395098 (Y-coordinates).

Sequence in context: A265691 A334430 A214614 * A265692 A392265 A370263

Adjacent sequences: A395091 A395092 A395093 * A395095 A395096 A395097

Keyword

nonn,tabf

Author

Rémy Sigrist, Apr 11 2026

Status

approved