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A050765 Composite n added to sum of its prime factors is nextprime(n). 5
38400, 59290, 89700, 93639, 155952, 356400, 682080, 1226907, 1468320, 1648640, 2592000, 2995200, 3595500, 3933644, 5845203, 5967360, 8860995, 8953560, 9748480, 11351340, 12819224, 13226976, 13712490, 16193520, 18375000, 19294436, 21206016, 25259520, 28297500 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson and Giovanni Resta, Table of n, a(n) for n = 1..1033 (terms < 10^12, first 500 terms from Donovan Johnson)

C. Rivera, See also related puzzle

EXAMPLE

nextprime(93639) = 93639 + (3+7+7+7+7+13) = 93683.

MATHEMATICA

Reap[For[n = 4, n <= 2*10^7, n = If[PrimeQ[n+1], n+2, n+1], If[n + Total[Times @@@ FactorInteger[n] ] == NextPrime[n], Print[n]; Sow[n]]]][[2, 1]] (* Jean-Fran├žois Alcover, Oct 18 2013 *)

cspfQ[n_]:=CompositeQ[n]&&NextPrime[n]==n+Total[Flatten[Table[ #[[1]], #[[2]]] &/@FactorInteger[n]]]; Select[Range[29*10^6], cspfQ] (* Harvey P. Dale, Oct 14 2017 *)

CROSSREFS

Cf. A050766, A050703, A050710, A105779, A235425.

Sequence in context: A138400 A248690 A050777 * A254852 A203792 A013873

Adjacent sequences:  A050762 A050763 A050764 * A050766 A050767 A050768

KEYWORD

nonn,nice

AUTHOR

Patrick De Geest, Sep 15 1999

EXTENSIONS

Offset corrected by Donovan Johnson, Oct 18 2013

STATUS

approved

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Last modified August 11 09:54 EDT 2020. Contains 336423 sequences. (Running on oeis4.)