A343902 T(n, k) is the k-th prime p such that (p-1)|A000010(n); irregular array read by rows.

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

Offset

3,1

Links

Table of n, a(n) for n=3..88.

Example

The irregular array T starts as follows:
2
2
2, 3
2
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3, 5, 7
2, 3
2, 3, 5
2, 3, 5
2, 3, 5
2, 3
2, 3, 7
2, 3, 5
2, 3, 5, 7
2, 3
2, 3
2, 3, 5
2, 3, 5, 11
2, 3, 5, 7
2, 3, 7
2, 3, 5, 7
2, 3, 5
2, 3, 5
2, 3, 7, 11
2, 3, 5

Prog

(PARI) row(n) = my(e=eulerphi(n)); forprime(p=2, e, if(e%(p-1)==0, print1(p, ", "))); print("")
array(rows) = for(x=3, rows+2, row(x))
array(10) \\ Print upper 10 rows of the array

Crossrefs

Cf. A000010, A343901, A343903.

Sequence in context: A085694 A258570 A257572 * A160493 A053760 A223942

Adjacent sequences: A343899 A343900 A343901 * A343903 A343904 A343905

Keyword

nonn,tabf

Author

Felix Fröhlich, May 03 2021

Status

approved