A128373 Irregular triangle read by rows: row n (n>=2) lists positions in the sequence A007318 where n appears.

4, 7, 8, 11, 13, 16, 19, 12, 22, 26, 29, 34, 37, 43, 46, 53, 17, 18, 56, 64, 67, 76, 79, 89, 92, 103, 106, 118, 23, 25, 121, 134, 137, 151, 154, 169, 172, 188, 191, 208, 24, 211, 229, 30, 33, 232, 251, 254, 274, 277, 298, 301, 323, 326, 349, 352, 376, 379, 404, 38

Offset: 2

Author

Nick Hobson, Mar 01 2007

Keywords

• easy
• nonn
• tabf

Examples

			In A007318, the number 2 appears in position 4, so the first row is 4. The number 3 appears in positions 7 and 8 in A007318, so the second row is 7, 8.
The irregular triangle begins:
   4
   7,  8
  11, 13
  16, 19
  12, 22, 26
  29, 34
  37, 43
  46, 53
  ...
		

Crossrefs

Cf. A003015, A003016, A007318, A059233.