a(n) = sigma_2(n)*Pell(n), where sigma_2(n) = A001157(n), the sum of squares of divisors of n.

A204272

a(n) = sigma_2(n)*Pell(n), where sigma_2(n) = A001157(n), the sum of squares of divisors of n.

Terms

    a(0) =1a(1) =10a(2) =50a(3) =252a(4) =754a(5) =3500a(6) =8450a(7) =34680a(8) =89635a(9) =309140a(10) =700402a(11) =2910600a(12) =5688370a(13) =20195500a(14) =50706500a(15) =160553712a(16) =329639810a(17) =1248615550a(18) =2398289458a(19) =8732957688a(20) =19306982500a(21) =56865638380a(22) =119281100930a(23) =461838762000a(24) =853941516771

External references