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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

Table of n, a(n) for n=1..56.

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

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Last modified April 19 10:33 EDT 2019. Contains 322252 sequences. (Running on oeis4.)