A309770 Numbers that are sums of one or more consecutive primes in more than one way.
5, 17, 23, 31, 36, 41, 53, 59, 60, 67, 71, 72, 83, 90, 97, 100, 101, 109, 112, 119, 120, 127, 131, 138, 139, 143, 152, 173, 180, 181, 187, 197, 199, 204, 210, 211, 221, 223, 228, 233, 240, 251, 258, 263, 269, 271, 276, 281, 287, 300, 304, 311, 323, 330, 331, 340, 349
Offset: 1
Keywords
Examples
5 is in the sequence because it can be written as either 5 or 2 + 3. 36 is the sequence because it can be written as either 5 + 7 + 11 + 13 or 17 + 19.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
- Eric Weisstein's World of Mathematics, Prime Sums
Programs
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Maple
N:= 1000: # for terms <= N P:= select(isprime, [2, seq(i,i=3..N,2)]): S:= [0,op(ListTools:-PartialSums(P))]: V:= Vector(N): for i from 1 to nops(S) do for j from i-1 to 1 by -1 do v:= S[i]-S[j]; if v > N then break fi; V[v]:= V[v]+1; od od: select(t -> V[t]>1, [$1..N]); # Robert Israel, Aug 22 2019
Formula
A054845(a(n)) > 1.
Comments