A378089 Irregular triangle read by rows in which row n lists the numbers k such that phi(k)/tau(k) = n.

1, 3, 8, 10, 18, 24, 30, 5, 9, 15, 28, 40, 72, 84, 90, 120, 7, 21, 26, 56, 70, 78, 108, 126, 168, 210, 34, 45, 52, 102, 140, 156, 252, 360, 420, 11, 33, 88, 110, 198, 264, 330, 13, 35, 39, 63, 76, 104, 105, 130, 228, 234, 280, 312, 390, 504, 540, 630, 840, 58, 98, 174, 294

Offset

1,2

Links

Table of n, a(n) for n=1..63.

Example

Triangle begins:
  n=1: 1, 3, 8, 10, 18, 24, 30;
  n=2: 5, 9, 15, 28, 40, 72, 84, 90, 120;
  n=3: 7, 21, 26, 56, 70, 78, 108, 126, 168, 210;
  n=4: 34, 45, 52, 102, 140, 156, 252, 360, 420;
  n=5: 11, 33, 88, 110, 198, 264, 330;
  n=6: 13, 35, 39, 63, 76, 104, 105, 130, 228, 234, 280, 312, 390, 504, 540, 630, 840;
  n=7: 58, 98, 174, 294;
  ...

Crossrefs

Cf. A000005 (tau), A000010 (phi).

Cf. A020488 (row 1), A062516 (row 2), A063469 (row 3), A063470 (row 4).

Cf. A112954 (row lengths), A175667 (1st column), A112955 (right column), A020491 (ordered terms).

Sequence in context: A020488 A064435 A079541 * A283757 A353078 A131725

Adjacent sequences: A378086 A378087 A378088 * A378090 A378091 A378092

Keyword

nonn,tabf

Author

Mohammed Yaseen, Nov 16 2024

Status

approved