A285731 - OEIS

A285731

Transpose of square array A285730.

1, 2, 1, 3, 2, 1, 2, 3, 2, 1, 5, 4, 3, 2, 1, 3, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3, 2, 1, 2, 7, 6, 5, 4, 3, 2, 1, 3, 4, 7, 6, 5, 4, 3, 2, 1, 5, 9, 8, 7, 6, 5, 4, 3, 2, 1, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 3, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 13, 6, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 7, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1

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

OFFSET

1,2

COMMENTS

See A285730.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..7260; the first 120 antidiagonals of array

EXAMPLE

The top left 25 x 4 corner of the array:

1 2 3 2 5 3 7 2 3 5 11 3 13 7 5 2 17 3 19 5 7 11 23 3 5

1 2 3 4 5 6 7 4 9 10 11 6 13 14 15 4 17 9 19 10 21 22 23 6 25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 8 17 18 19 20 21 22 23 12 25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

MATHEMATICA

With[{nn = 14}, Function[s, Table[s[[n, #]] &[k - n + 1], {k, nn}, {n, k, 1, -1}]]@ MapIndexed[PadRight[#1, nn, First@ #2] &, Table[FoldList[Times, Reverse@ Flatten[FactorInteger[n] /. {p_, e_} /; e > 0 :> ConstantArray[p, e]]], {n, nn}]]] // Flatten (* Michael De Vlieger, Apr 28 2017 *)

PROG

(Scheme) (define (A285731 n) (A285730bi (A004736 n) (A002260 n))) ;; For A285730bi see A285730.

(Python)

from sympy import primefactors

def a006530(n): return 1 if n==1 else max(primefactors(n))

def A(n, k): return a006530(n) if k==1 else a006530(n)*A(n/a006530(n), k - 1)

for n in range(1, 21): print [A(n - k + 1, k) for k in range(1, n + 1)] # Indranil Ghosh, Apr 28 2017

CROSSREFS

Transpose of A285730.

Cf. A006530 (the topmost row).

Sequence in context: A005678 A296976 A182321 * A114905 A200651 A126597

Adjacent sequences: A285728 A285729 A285730 * A285732 A285733 A285734

KEYWORD

nonn,tabl

AUTHOR

Antti Karttunen, Apr 28 2017

STATUS

approved