A268733 a(n) = A000203(A251720(n))

28, 78, 248, 684, 1862, 3294, 6140, 9144, 16590, 27872, 37734, 59094, 75812, 90864, 121878, 171780, 219542, 257244, 328104, 378362, 432240, 530964, 627570, 785078, 969714, 1071512, 1157004, 1271270, 1366974, 1649024, 2145924

Offset

1,1

Comments

Let p=prime(n)=A000040(n) and q=prime(n+1)=A000040(n+1) then a(n)=sigma(p^2*q)=1+p+q+p^2+ p*q+p^2*q.

Links

Table of n, a(n) for n=1..31.

Mathematica

p=1; Table[p=NextPrime[p]; q=NextPrime[p]; 1+p+q+p^2+p*q+p^2*q, {20}]

Prog

(PARI) p=1; for(n=1, 20, p=nextprime(p+1); q=nextprime(p+1); print1(sigma(p^2*q)", "))

Crossrefs

Cf. A000040, A000203, A251720.

Sequence in context: A341175 A044166 A044547 * A119178 A161935 A039415

Adjacent sequences: A268730 A268731 A268732 * A268734 A268735 A268736

Keyword

nonn

Author

Zak Seidov, Feb 12 2016

Status

approved