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A303217 A(n,k) is the n-th index of a Fibonacci number with exactly k distinct prime factors; square array A(n,k), n>=1, k>=1, read by antidiagonals. 19
3, 8, 4, 15, 9, 5, 20, 16, 10, 6, 30, 24, 18, 12, 7, 40, 36, 27, 21, 14, 11, 70, 48, 42, 28, 33, 19, 13, 60, 81, 54, 44, 32, 35, 22, 17, 80, 72, 104, 56, 45, 52, 37, 25, 23, 90, 84, 110, 105, 64, 50, 55, 38, 26, 29, 140, 126, 88, 112, 136, 78, 57, 74, 39, 31, 43 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Alois P. Heinz, Antidiagonals n = 1..18, flattened

FORMULA

A000045(A(n,k)) = A303218(n,k).

A001221(A000045(A(n,k))) = k.

EXAMPLE

Square array A(n,k) begins:

   3,  8, 15, 20, 30,  40,  70,  60,  80,  90, ...

   4,  9, 16, 24, 36,  48,  81,  72,  84, 126, ...

   5, 10, 18, 27, 42,  54, 104, 110,  88, 165, ...

   6, 12, 21, 28, 44,  56, 105, 112,  96, 256, ...

   7, 14, 33, 32, 45,  64, 136, 114, 100, 258, ...

  11, 19, 35, 52, 50,  78, 148, 128, 108, 266, ...

  13, 22, 37, 55, 57,  92, 152, 130, 132, 296, ...

  17, 25, 38, 74, 63,  95, 164, 135, 138, 304, ...

  23, 26, 39, 77, 66,  99, 182, 147, 156, 322, ...

  29, 31, 46, 85, 68, 102, 186, 154, 184, 369, ...

MAPLE

F:= combinat[fibonacci]: with(numtheory):

A:= proc() local h, p, q; p, q:= proc() [] end, 2;

      proc(n, k)

        while nops(p(k))<n do q:= q+1;

          h:= nops(factorset(F(q)));

          p(h):= [p(h)[], (q)]

        od; p(k)[n]

      end

    end():

seq(seq(A(n, 1+d-n), n=1..d), d=1..12);

CROSSREFS

Columns k=2-16 give: A114842, A114841, A114843, A114840, A114839, A114838, A114837, A114836, A114826, A114825, A114824, A114823, A117529, A117551, A117550.

Row n=1 gives: A060320.

Cf. A000045, A001221, A022307, A303215, A303218.

Sequence in context: A225456 A212886 A127438 * A106292 A072247 A051359

Adjacent sequences:  A303214 A303215 A303216 * A303218 A303219 A303220

KEYWORD

nonn,tabl

AUTHOR

Alois P. Heinz, Apr 19 2018

STATUS

approved

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Last modified November 11 18:50 EST 2019. Contains 329031 sequences. (Running on oeis4.)