This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A175132 Numbers n such that p(i)+p(i+1)=n*(n+1)/2, p(i) i-th prime, n an integer. Sum of two consecutive primes is a triangular number. 1
 8, 12, 15, 20, 23, 24, 35, 43, 44, 59, 60, 71, 75, 80, 84, 92, 99, 104, 128, 140, 147, 148, 155, 159, 200, 204, 216, 231, 251, 264, 288, 295, 303, 332, 336, 339, 344, 363, 384, 395, 420, 439, 440, 451, 455, 463, 467, 468, 495, 528, 539, 543, 560, 587, 588, 608 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A000217(n)=A001043(k) LINKS EXAMPLE 17+19=36, 36 = 8*9/2, n=8 for primes 17,19. 37+41=78, 78 = 12*13/2, n=12 for primes 37,41. PROG (PARI) lista(nn) = {for (i=1, nn, vsp = 1 + 8 *(prime(i) + prime(i+1)); if (issquare(vsp), v  = sqrtint(vsp) - 1; if (v % 2 ==0, print1(v/2, ", "); ); ); ); } \\ Michel Marcus, Jun 02 2013 CROSSREFS Cf. A000217, A001043, A000040 Sequence in context: A062373 A180690 A194592 * A287373 A031034 A152758 Adjacent sequences:  A175129 A175130 A175131 * A175133 A175134 A175135 KEYWORD easy,nonn AUTHOR Ctibor O. Zizka, Feb 19 2010 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 April 19 10:33 EDT 2019. Contains 322252 sequences. (Running on oeis4.)