This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A090788 Numbers that can be expressed as the difference of the squares of primes in just two distinct ways. 24
 72, 360, 432, 528, 768, 888, 960, 1032, 1080, 1128, 1272, 1392, 1488, 1512, 1608, 1632, 1728, 1920, 2088, 2112, 2232, 2352, 2400, 2448, 2568, 2688, 2808, 3048, 3168, 3240, 3288, 3480, 3648, 3768, 4008, 4032, 4128, 4248, 4272, 4392, 4488, 4512, 4992 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 72 = 11^2 - 7^2 = 19^2 - 17^2. PROG (PARI) i=4; while(i<=5000, k=0; m=2; while(m*m<=i, if(i%(2*m)==0, a=(i/m-m)/2; b=a+m; if(isprime(a)&&isprime(b), k+=1)); m+=2); if(k==2, print1(i, ", ")); i+=4) \\ Antonio Roldán, Nov 06 2018 CROSSREFS Cf. A078667, A090781, A090782. Sequence in context: A157909 A107314 A223472 * A192792 A303621 A084479 Adjacent sequences:  A090785 A090786 A090787 * A090789 A090790 A090791 KEYWORD nonn AUTHOR Ray Chandler, Feb 14 2004 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 July 17 23:21 EDT 2019. Contains 325109 sequences. (Running on oeis4.)