cp's OEIS Frontend

A076430 Sum of squares of numbers that cannot be written as t*p(n) + u*p(n+1) for nonnegative integers t,u, where p(n) is the n-th prime.

%I A076430 #5 Apr 03 2025 22:30:57
%S A076430 1,70,1610,22715,170170,675376,2224824,5696295,21057190,52798270,
%T A076430 111385170,261955560,414410780,628310711,1187225546,2369546790,
%U A076430 3631067090,5339542890,8459444455,10969197540,15154637940,22349763995
%N A076430 Sum of squares of numbers that cannot be written as t*p(n) + u*p(n+1) for nonnegative integers t,u, where p(n) is the n-th prime.
%D A076430 Fred. Schuh, Vragen betreffende een onbepaalde vergelijking, Nieuw Tijdschrift voor Wiskunde, 52 (1964-1965) 193-198.
%F A076430 a(n) = p(n) * p(n+1) * (p(n)-1) * (p(n+1)-1) * (p(n)*p(n+1)-p(n)-p(n+1)) / 12.
%p A076430 seq(ithprime(n)*ithprime(n+1)*(ithprime(n)-1)*(ithprime(n+1)-1)*(ithprime(n)*ithprime(n+1)-ithprime(n)-ithprime(n+1))/12,n=1..30);
%Y A076430 Cf. A076389, A076429.
%K A076430 nonn
%O A076430 1,2
%A A076430 _Floor van Lamoen_, Oct 10 2002