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A154587 Numbers that can be expressed both as the sum of first prime numbers and as the sum of first nonprime numbers. 4

%I #37 Mar 06 2018 11:16:20

%S 0,5,28,71208,74139,9260197734,12374540078,7574780746329,

%T 11101148723618,102581905748236,3325997869054417,

%U 2886018916559052244845,46437379006448216748610,120197329614203475099994

%N Numbers that can be expressed both as the sum of first prime numbers and as the sum of first nonprime numbers.

%C Is this sequence finite?

%C Intersection of A007504 and A053767 generates A294174. - _R. J. Mathar_, Jan 17 2009

%C Heuristically, the sequence is infinite with about 2 sqrt(log x) members up to x. - _Charles R Greathouse IV_, Aug 14 2013

%H Giovanni Resta, <a href="/A154587/a154587.c.txt">C program</a>

%e 5 = 2+3 = 1+4. 28 = 2+3+5+7+11 = 1+4+6+8+9.

%p P:=proc(q) local a,b,c,d,n; a:=0; b:=0; c:=0; d:=0; print(a);

%p for n from 1 to q do b:=nextprime(b); a:=a+b;

%p while c<a do d:=d+1; if not isprime(d) then c:=c+d; fi; od;

%p if c=a then print(a); fi; od; end: P(10^9);# _Paolo P. Lava_, Feb 23 2018

%t With[{p = Prime@ Range[10^7]}, {0}~Join~Intersection[Accumulate@ p, Accumulate@ Complement[Range@ Max@ p, p]]] (* _Michael De Vlieger_, Feb 25 2018 *)

%Y Intersection of A007504 and A051349. - _R. J. Mathar_, Jan 17 2009

%Y Cf. A133784, A294174.

%K nonn,more,nice

%O 1,2

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Jan 15 2009

%E Corrected definition and a(6)-a(7) from _R. J. Mathar_, Jan 17 2009

%E a(8)-a(11) from _Donovan Johnson_, Feb 19 2009

%E a(12)-a(14) from _Giovanni Resta_, Aug 14 2013

%E Edited and a(1)=0 prepended by _Max Alekseyev_, Feb 10 2018

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Last modified June 1 04:03 EDT 2024. Contains 373010 sequences. (Running on oeis4.)