Let p>5 be a prime. Motivated by the known formulae
∑k=1∞(−1)k/(k3(k2k))=−2ζ(3)/5 and
∑k=0∞(k2k)2/((2k+1)16k)=4G/π(whereG=\sum_{k=0}^\infty(-1)^k/(2k+1)^2istheCatalanconstant),weshowthat∑k=1(p−1)/2k3(k2k)(−1)k≡−2Bp−3(modp),$
k=(p+1)/2∑p−1(2k+1)16k(k2k)2≡−47p2Bp−3(modp3), and
k=0∑(p−3)/2(2k+1)16k(k2k)2≡−2qp(2)−pqp(2)2+125p2Bp−3(modp3), where
B0,B1,… are Bernoulli numbers and qp(2) is the Fermat quotient
(2p−1−1)/p.