A338240 Irregular triangle read by rows; the n-th row is the colexicographically earliest finite subset of distinct positive numbers that do not appear in previous rows and summing to a prime number.

2, 3, 1, 4, 5, 7, 8, 9, 11, 13, 6, 10, 15, 17, 19, 12, 14, 21, 23, 16, 25, 20, 27, 29, 31, 18, 22, 33, 24, 35, 37, 28, 39, 41, 43, 26, 45, 47, 30, 49, 32, 51, 53, 34, 55, 36, 38, 57, 59, 61, 40, 63, 42, 65, 67, 44, 69, 71, 73, 48, 50, 75, 54, 77, 79, 46, 81, 83

Offset

1,1

Comments

This sequence is a permutation of the natural numbers.

Each prime number appears alone on some row.

Sequence A338141 gives row sums.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Scatterplot of (n, a(n)-n) for n = 1..10000

Rémy Sigrist, PARI program for A338240

Index entries for sequences that are permutations of the natural numbers

Example

Triangle begins:
  1:  [2]
  2:  [3]
  3:  [1, 4]
  4:  [5]
  5:  [7]
  6:  [8, 9]
  7:  [11]
  8:  [13]
  9:  [6, 10, 15]
  10: [17]
  11: [19]
  12: [12, 14, 21]
  13: [23]
  14: [16, 25]
  15: [20, 27]

Prog

(PARI) See Links section.

Crossrefs

Cf. A338141 (row sums).

Sequence in context: A071517 A305433 A257681 * A265755 A341130 A330139

Adjacent sequences: A338237 A338238 A338239 * A338241 A338242 A338243

Keyword

nonn,tabf

Author

Rémy Sigrist, Oct 18 2020

Status

approved