The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A298704 Numbers that are the smallest of four consecutive primes, no two of which, along with the product of the other two, sum to a nonprime. 1
 10942177, 33612487, 38370391, 350212139, 431472421, 594652609, 616335793, 795968851, 867683191, 885354367, 982828577, 1058353099, 1278213241, 1367427883, 1966024733, 2329521127, 2734073753, 2959246399, 3067739581 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Hans Havermann, Table of n, a(n) for n = 1..800 EXAMPLE 10942177, 10942187, 10942201, 10942207 are four consecutive primes. The six ways of adding the product of two of these to the sum of the other two yields 119731368805507, 119731521995971, 119731587649027, 119731631417971, 119731697071087, 119731850261971, all of which are prime. So 10942177 is a term of the sequence. MAPLE with(numtheory): with(combinat): P:=proc(q) local a, b, c, d, k, n, ok, x, y; a:=0; b:=10942177; c:=10942187; d:=10942201; for n from 1 to q do ok:=1; a:=b; b:=c; c:=d; d:=nextprime(d); x:={a, b, c, d}; y:=choose(x, 2); for k from 1 to 6 do if not isprime(convert(y[k], `*`)+convert(x minus y[k], `+`)) then ok:=0; break; fi; od; if ok=1 then print(a); fi; od; end: P(10^20); # Paolo P. Lava, Jan 25 2018 CROSSREFS Sequence in context: A205464 A202470 A224639 * A308079 A114680 A329224 Adjacent sequences:  A298701 A298702 A298703 * A298705 A298706 A298707 KEYWORD nonn AUTHOR Hans Havermann, Jan 24 2018 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 14 18:47 EDT 2021. Contains 343900 sequences. (Running on oeis4.)