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A050777 First occurrence from iterated procedure 'composite k added to sum of its prime factors reaches a prime' yielding n skipped primes. 0
38400, 6, 10, 26, 8, 18, 4, 39, 16, 30, 27, 32, 126, 76, 92, 87, 63, 77, 122, 49, 62, 120, 56, 50, 45, 117, 110, 196, 88, 102, 75, 246, 171, 72, 70, 234, 60, 469, 66, 217, 260, 198, 244, 387, 550, 230, 528, 362, 519, 764, 500, 494, 566, 376, 548, 386, 526, 481 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..57.

C. Rivera, Puzzle 66 - The SOPF sequences

EXAMPLE

a(1)=38400 + (2+2+2+2+2+2+2+2+2+3+5+5) = 38431. '0' primes between 38400 and 38431.

a(2)=6 + (2+3) = 11. '1' prime between 6 and 11.

a(3)=10 + (2+5) = 17. '2' primes between 10 and 17.

MATHEMATICA

a[n_]:=Length[Select[Range[n+1, NestWhile[#+Total[Times@@@FactorInteger[#]]&, n, !PrimeQ[#]&]-1], PrimeQ]]; t={38400}; Do[i=4; While[a[i]!=k, If[PrimeQ[i+1], i+=2, i++]]; AppendTo[t, i], {k, 57}]; t (* Jayanta Basu, Jun 01 2013 *)

CROSSREFS

Cf. A050765, A050768-A050776, A050703.

Sequence in context: A298427 A138400 A248690 * A050765 A254852 A203792

Adjacent sequences:  A050774 A050775 A050776 * A050778 A050779 A050780

KEYWORD

nonn

AUTHOR

Patrick De Geest, Sep 15 1999

STATUS

approved

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Last modified November 21 22:40 EST 2019. Contains 329383 sequences. (Running on oeis4.)