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A242255
Primes-greedy summable primes, as defined at A242252.
5
5, 7, 13, 19, 31, 43, 61, 73, 103, 109, 139, 149, 151, 181, 191, 193, 199, 229, 241, 251, 271, 283, 293, 313, 347, 349, 419, 421, 431, 433, 463, 523, 557, 571, 587, 601, 619, 641, 643, 661, 701, 719, 797, 811, 821, 823, 829, 839, 859, 883, 929, 1021, 1031
OFFSET
1,1
COMMENTS
See A242252 for the definitions of greedy sum and summability. A242255 and A242256 partition the primes.
LINKS
EXAMPLE
Four primes-greedy primes with matching prime-greedy sums are shown here:
a(1) = 5 = 3 + 2
a(2) = 7 = 5 + 2
a(3) = 13 = 11 + 2
a(12) = 149 = 139 + 7 + 3
MATHEMATICA
z = 200; s = Table[Prime[n], {n, 1, z}]; t = Table[{s[[n]], #, Total[#] == s[[n]]} &[ DeleteCases[-Differences[FoldList[If[#1 - #2 >= 0, #1 - #2, #1] &, s[[n]], Reverse[Select[s, # < s[[n]] &]]]], 0]], {n, z}]; r[n_] := s[[n]] - Total[t[[n]][[2]]]; tr = Table[r[n], {n, 2, z}] (* A242252 *)
c = Table[Length[t[[n]][[2]]], {n, 2, z}] (* A242253 *)
f = 1 + Flatten[Position[tr, 0]] (* A242254 *)
Prime[f] (* A242255 *)
f1 = Prime[Complement[Range[Max[f]], f]] (* A242256 *)
(* Peter J. C. Moses, May 06 2014 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, May 09 2014
STATUS
approved