A182081 Next semiprime after the partial sum of the first n semiprimes.
6, 14, 21, 33, 46, 62, 82, 106, 129, 155, 187, 221, 259, 295, 334, 381, 427, 478, 533, 591, 649, 713, 778, 849, 921, 995, 1077, 1165, 1253, 1337, 1437, 1522, 1618, 1711, 1814, 1927, 2041, 2159, 2279, 2402, 2533, 2643, 2773, 2906, 3039, 3183, 3326, 3466, 3611
Offset: 1
Examples
a(10) = 155 because 4 + 6 + 9 + 10 + 14 + 15 + 21 + 22 + 25 + 26 = 152, and the next semiprime after 152 is 155.
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..1000
Programs
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Maple
h:= proc(m) local k; for k from m+1 while isprime(k) or add (i[2], i=ifactors(k)[2])<>2 do od; k end: b:= proc(n) b(n):= h(b(n-1)) end: b(0):=0: s:= proc(n) s(n):= b(n) +s(n-1) end: s(0):=0: a:= n-> h(s(n)): seq (a(n), n=1..60); # Alois P. Heinz, Apr 10 2012
Extensions
More terms from Alois P. Heinz, Apr 10 2012
Comments