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A268733
a(n) = A000203(A251720(n))
1
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.
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
KEYWORD
nonn
AUTHOR
Zak Seidov, Feb 12 2016
STATUS
approved