# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a060108
Showing 1-1 of 1

%I A060108 #7 Dec 12 2017 03:44:14
%S A060108 2,22,40,92,210,260,442,672,950,1162,1520,1650,2072,2380,2882,3060,
%T A060108 4030,5370,5612,6112,7740,8030,8932,9560,9882,10542,14950,15352,16590,
%U A060108 17442,21540,22022,23002,23500,28222,29330,31032,32782,34580,35190
%N A060108 Sequence of sums based on primes = 7 mod 8.
%H A060108 C. Popescu, <a href="http://www.jstor.org/stable/2695534">Problem 10852</a>, American Mathematical Monthly, Vol. 108 (2001), p. 171.
%H A060108 C. Popescu, Roy Barbara and Omran Kouba, <a href="http://www.jstor.org/stable/2695348">A Sum Related to Quadratic Residues: 10852</a>, American Mathematical Monthly, Vol. 109 (2002), p. 208.
%F A060108 a(n) = Sum_{k=1..(p-1)/2} floor(k^2/p+1/2) where p is n-th prime congruent to 7 mod 8 (i.e. A007522(n)).
%F A060108 a(n) = (A007522(n)^2 - 1)/24. See 2nd link. - _Michel Marcus_, Dec 12 2017
%e A060108 For n=2, p=A007522(2)=23, so a(2)=0+0+0+1+1+2+2+3+4+4+5=22.
%o A060108 (PARI) lista(nn) = {forprime(p=2, nn, if ((p % 8) == 7, print1((p^2-1)/24, ", ")););} \\ _Michel Marcus_, Dec 12 2017
%Y A060108 Cf. A007522.
%K A060108 easy,nonn
%O A060108 1,1
%A A060108 _Marc LeBrun_, Feb 27 2001

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE