

A064961


Compositethenprime recurrence; a(2n) = a(2n1)th composite and a(2n+1) = a(2n)th prime and a(1) = 1.


2



1, 4, 7, 14, 43, 62, 293, 366, 2473, 2892, 26317, 29522, 344249, 376259, 5429539, 5831545, 101291779, 107457490, 2198218819, 2310909505, 54720307351, 57128530327, 1543908890351, 1603146693999, 48871886538151, 50527531769529, 1720466016680911, 1772475453490311
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OFFSET

1,2


LINKS



MATHEMATICA

Composite[n_Integer] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; a = {1, 4}; b = 4; Do[ If[ !PrimeQ[b], b = Prime[b], b = Composite[b]]; a = Append[a, b], {n, 1, 23}]; a


CROSSREFS

Cf. A007097, A006508 & A064960, see also A057450, A057451, A057452, A057453, A057456 & A057457 and A049076, A049077, A049078, A049079, A049080 & A049081.


KEYWORD

nonn


AUTHOR



EXTENSIONS

a(24)a(26) corrected and a(27)a(28) added by Chai Wah Wu, Aug 22 2018


STATUS

approved



