cp's OEIS Frontend

A357957 a(n) = A005259(n)^5 - A005258(n)^2.

%I A357957 #13 Nov 03 2022 04:51:38
%S A357957 0,3116,2073071232,6299980938881516,39141322964380888600000,
%T A357957 368495989505416178203682748116,4552312485541626792249211584618373944,
%U A357957 68109360474242016374599574592870648425552876,1174806832391451114413440151405736019461523615095744
%N A357957 a(n) = A005259(n)^5 - A005258(n)^2.
%C A357957 Conjectures:
%C A357957 1) a(p - 1) == 0 (mod p^5) for all primes p >= 5 (checked up to p = 271).
%C A357957 2) a(p^r - 1) == a(p^(r-1) - 1) ( mod p^(3*r+3) ) for r >= 2 and all primes p >= 5.
%C A357957 These are stronger supercongruences than those satisfied separately by the two types of Apéry numbers A005258 and A005259.
%C A357957 3) Put u(n) = A005259(n)^5 / A005258(n)^2. Then u(p^r - 1) == u(p^(r-1) - 1) ( mod p^(3*r+3) ) for r >= 2 and all primes p >= 5.
%F A357957 a(n) = ( Sum_{k = 0..n} binomial(n,k)^2*binomial(n+k,k)^2 )^5 - ( Sum_{k = 0..n} binomial(n,k)^2*binomial(n+k,k) )^2.
%F A357957 a(n*p^r - 1) == a(n*p^(r-1) - 1) ( mod p^(3*r) ) for positive integers n and r and for all primes p >= 5.
%F A357957 a(n) = hypergeom([-n, -n, 1 + n, 1 + n], [1, 1, 1], 1)^5 - hypergeom([1 + n, -n, -n], [1, 1], 1)^2. - _Peter Luschny_, Nov 01 2022
%e A357957 a(7) = 4552312485541626792249211584618373944 = (2^3)*(3^3)*(7^5)*29*107* 404116272977592231282158029 == 0 (mod 7^5).
%p A357957 seq(add(binomial(n,k)^2*binomial(n+k,k)^2, k = 0..n)^5 - add(binomial(n,k)^2*binomial(n+k,k), k = 0..n)^2, n = 0..20);
%p A357957 # Alternatively:
%p A357957 a := n -> hypergeom([-n, -n, 1 + n, 1 + n], [1, 1, 1], 1)^5 - hypergeom([1 + n, -n, -n], [1, 1], 1)^2: seq(simplify(a(n)), n=0..8); # _Peter Luschny_, Nov 01 2022
%Y A357957 Cf. A005258, A005259, A212334, A352655, A357567, A357568, A357569, A357956, A357958, A357959, A357960.
%K A357957 nonn,easy
%O A357957 0,2
%A A357957 _Peter Bala_, Oct 24 2022