399851303domain: NPropertiesPrimalityPrimeyesAppears in sequencesDenominator of the harmonic mean of the first n heptagonal numbers.at n=7A247115Numerators of the partial sums of the reciprocals of twice the heptagonal numbers (k + 1)*(5*k + 2) = A135706(k+1) = 2*A000566(k+1), for k >= 0.at n=7A294826Prime numbersat n=21328821