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A103791 Index of the first occurrence of A019565(2n-1) in sequence A103790. 1
2, 4, 8, 29, 24, 78, 65, 90, 449, 280, 400, 124, 935, 589, 1743, 325, 2001, 2863, 3150, 2026, 5680, 5156, 4016, 10403, 22626, 2358, 19242, 14356, 19543, 7666, 20555, 29104, 64045, 56438, 84993, 15346, 37400, 13663, 83487, 58651, 162225, 111880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

EXAMPLE

A103790(2)=1*2*1-1; => a(1)=2

A103790(4)=3*2*2-1; => a(2)=4

MATHEMATICA

A019565 = Function[tn, k1 = tn; o = 1; tt = 1; While[k1 > 0, k2 = Mod[k1, 2]; If[k2 == 1, tt = tt*Prime[o]]; k1 = (k1 - k2)/2; o = o + 1]; tt]; Array[fa, {1, 500}]; Do[fa[n] = 0, {n, 1, 500}]; n = 2; npd = Prime[n]; ct = 1; wt = 1; While[wt < 69, cr = (ct + 1)/2; If[fa[cr] == 0, fa[cr] = n; While[fa[wt] > 0, Print[fa[wt]]; wt = wt + 1]]; n = n + 1; npd = Prime[n]; ct = 1; tt = ct; cp = npd + A019565[tt]; While[ ! (PrimeQ[cp]), ct = ct + 1; tt = ct; cp = npd + A019565[tt]]]

CROSSREFS

Cf. A019565, A103790.

Sequence in context: A151340 A134316 A049461 * A269569 A018346 A006398

Adjacent sequences:  A103788 A103789 A103790 * A103792 A103793 A103794

KEYWORD

nonn

AUTHOR

Lei Zhou, Feb 16 2005

STATUS

approved

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Last modified May 28 16:37 EDT 2022. Contains 354119 sequences. (Running on oeis4.)