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A308968 Table, read by rows: row n contains the prime factors of A001008(n) (numerator of n-th harmonic number), with multiplicity. 5
1, 3, 11, 5, 5, 137, 7, 7, 3, 11, 11, 761, 7129, 11, 11, 61, 97, 863, 13, 13, 509, 29, 43, 919, 1049, 1117, 29, 41233, 17, 17, 8431, 37, 1138979, 19, 19, 39541, 37, 7440427, 5, 11167027, 18858053, 3, 23, 23, 53, 227, 761, 583859, 5, 577, 467183, 109, 312408463 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 1 is taken to be {1} instead of being empty, by convention.

Length, first = smallest and last = largest term of the rows are given in A308967, A308970 and A308971, respectively. See A308969 for prime divisors without repetition.

LINKS

Table of n, a(n) for n=1..53.

M. F. Hasler, Rows 1 through 170.

EXAMPLE

   n | A001008(n) written as product of primes

-----+---------------------------------------------

   1 | 1 (empty product)

   2 | 3

   3 | 11

   4 | 5 * 5

   5 | 137

   6 | 7 * 7

   7 | 3 * 11 * 11

   8 | 761

   9 | 7129

  10 | 11 * 11 * 61

  11 | 97 * 863

  12 | 13 * 13 * 509

  13 | 29 * 43 * 919

  14 | 1049 * 1117

  15 | 29 * 41233

  16 | 17 * 17 * 8431

  17 | 37 * 1138979

  18 | 19 * 19 * 39541

  19 | 37 * 7440427

  20 | 5 * 11167027

etc.

PROG

(PARI) A308968_row(n)={if(n>1, concat(apply(f->vector(f[2], i, f[1]), Col(factor(A001008(n)))~)), [1])}

CROSSREFS

Cf. A001008, A308967 (row lengths, for n > 1).

Cf. A308969 (prime divisors without repetition), A308970 (column 1 = first / smallest term of each row), A308971 (last / greatest term in each row).

Sequence in context: A226625 A210610 A188950 * A084466 A084462 A156320

Adjacent sequences:  A308965 A308966 A308967 * A308969 A308970 A308971

KEYWORD

nonn,tabf

AUTHOR

M. F. Hasler, Jul 03 2019

STATUS

approved

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Last modified May 8 19:28 EDT 2021. Contains 343666 sequences. (Running on oeis4.)