A142593 - OEIS

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A142593

Irregular triangle read by rows: row n gives successive exponents in prime factorization of A141900(n).

4

1, 2, 1, 3, 1, 4, 1, 1, 5, 1, 1, 6, 1, 1, 1, 7, 1, 1, 1, 8, 3, 1, 1, 9, 3, 1, 1, 10, 3, 1, 1, 1, 11, 3, 1, 1, 1, 12, 3, 1, 1, 1, 1, 13, 3, 1, 1, 1, 1, 14, 3, 1, 1, 1, 1, 15, 3, 1, 1, 1, 1, 16, 3, 1, 1, 1, 1, 1, 17, 3, 1, 1, 1, 1, 1, 18, 3, 1, 1, 1, 1, 1, 1, 19, 3, 1, 1, 1, 1, 1, 1, 20, 3, 1, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..95.

David Applegate, Maple program which generates this triangle [The command hpat(n); returns the n-th row in an encoded form.]

N. J. A. Sloane, Rows 1 through 50 of the triangle

EXAMPLE

Triangle begins:

1

2 1

3 1

4 1 1

5 1 1

6 1 1 1

7 1 1 1

8 3 1 1

9 3 1 1

10 3 1 1 1

11 3 1 1 1

12 3 1 1 1 1

Row 8 = [8,3,1,1] because A141900(8) = 2^8*3^3*5*7 = 241920.

CROSSREFS

Cf. A141586, A141900, A142594.

Sequence in context: A195838 A195837 A123539 * A360285 A226248 A102547

Adjacent sequences: A142590 A142591 A142592 * A142594 A142595 A142596

KEYWORD

nonn,tabf

AUTHOR

David Applegate, Tim Kunisky (tkunisky(AT)gmail.com), Gerry Manoim (gerrymanoim(AT)gmail.com) and N. J. A. Sloane, Sep 25 2008

STATUS

approved