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A247177 Primes p with property that the sum of the squares of the successive gaps between primes <= p is a prime number. 4

%I #25 Jun 03 2020 12:13:21

%S 5,13,29,41,89,97,139,173,179,263,269,281,307,337,353,431,439,461,487,

%T 499,509,569,607,613,641,643,661,709,739,761,809,823,839,857,919,941,

%U 967,991,1031,1039,1061,1117,1129,1163,1171,1201,1229,1277,1381,1399

%N Primes p with property that the sum of the squares of the successive gaps between primes <= p is a prime number.

%C If A074741(n) is prime, then prime(n+1) is in this sequence. - _Michel Marcus_, Jan 12 2015

%H Abhiram R Devesh, <a href="/A247177/b247177.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=5; primes less than or equal to 5: [2, 3, 5]; squares of prime gaps: [1, 4]; sum of squares of prime gaps: 5.

%e a(2)=13; primes less than or equal to 13: [2, 3, 5, 7, 11, 13]; squares of prime gaps: [1, 4, 4, 16, 4]; sum of squares of prime gaps: 29.

%o (Python)

%o from sympy import nextprime, isprime

%o p = 2

%o s = 0

%o while s < 8000:

%o np = nextprime(p)

%o if isprime(s):

%o print(p)

%o d = np - p

%o s += d*d

%o p = np

%o (PARI) listp(nn) = {my(s = 0); my(precp = 2); forprime (p=3, nn, if (isprime(ns = (s + (p - precp)^2)), print1(p, ", ")); s = ns; precp = p;);} \\ _Michel Marcus_, Jan 12 2015

%Y Cf. A074741 (sum of squares of gaps between consecutive primes).

%K nonn,easy

%O 1,1

%A _Abhiram R Devesh_, Nov 22 2014

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Last modified September 17 21:09 EDT 2024. Contains 375990 sequences. (Running on oeis4.)