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 A051395 Numbers n such that n^2 is a sum of 4 consecutive primes. 11
 6, 18, 24, 42, 48, 70, 144, 252, 258, 358, 378, 388, 396, 428, 486, 506, 510, 558, 608, 644, 864, 886, 960, 974, 1022, 1046, 1326, 1362, 1392, 1398, 1422, 1434, 1442, 1468, 1476, 1592, 1604, 1676, 1820, 1950, 2016, 2068, 2140, 2288, 2430, 2460 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First of four consecutive primes in A206280. LINKS Charles R Greathouse IV and Zak Seidov, Table of n, a(n) for n = 1..10783 (First 3400 terms from Charles R Greathouse IV) FORMULA n such that n^2 = sum_{i=k..k+3} prime(i) for some k. EXAMPLE a(1)=6 because 6*6=5+7+11+13; a(2)=18 because 18*18=324=73+79+83+89. PROG (PARI) lista(nn) =  {pr = primes(nn); for (i = 1, nn - 3, s = pr[i] + pr[i+1] + pr[i+2] + pr[i+3]; if (issquare(s), print1(sqrtint(s), ", ")); ); } \\ Michel Marcus, Oct 02 2013 (PARI) is(n)=n*=n; my(p=precprime(n\4), q=nextprime(n\4+1), r, s); if(n < 3*q+p+8, r=precprime(p-1); s=n-p-q-r; ispseudoprime(s) && (s == precprime(r-1) || s == nextprime(q+1)), r=nextprime(q+1); s=n-p-q-r; ispseudoprime(s) && (s == precprime(p-1) || s == nextprime(r+1))) \\ Charles R Greathouse IV, Oct 02 2013 CROSSREFS Cf. A072849, A206280. Sequence in context: A028887 A283118 A274536 * A256266 A228104 A028558 Adjacent sequences:  A051392 A051393 A051394 * A051396 A051397 A051398 KEYWORD easy,nonn AUTHOR Zak Seidov, Jun 21 2003 EXTENSIONS Corrected and extended by Don Reble, Nov 20 2006 STATUS approved

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Last modified October 16 09:29 EDT 2019. Contains 328056 sequences. (Running on oeis4.)