A103791 Index of the first occurrence of A019565(2n-1) in sequence A103790.

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

Offset: 1

Author

Lei Zhou, Feb 16 2005

Keywords

• nonn

Examples

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

Crossrefs

Cf. A019565, A103790.

Programs

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]]]