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A228432 Sum_{i=1..floor(prime(n)/4)} floor(sqrt(i*prime(n))). 1
0, 0, 2, 2, 7, 14, 24, 25, 37, 70, 71, 114, 140, 143, 170, 234, 274, 310, 357, 399, 444, 498, 552, 660, 784, 850, 856, 926, 990, 1064, 1310, 1395, 1564, 1574, 1850, 1859, 2054, 2173, 2277, 2494, 2623, 2730, 2986, 3104, 3234, 3246, 3656, 4085, 4235, 4370 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
If p = prime(n) in A002145 and n>3, or said differently, if n in A080148 and n>1, then a(n) = A081115(n).
LINKS
S. A. Shirali, A family portrait of primes -- a case study in discrimination, Math. Mag., Vol. 70, No. 4 (Oct. 1997), pp. 263-272.
EXAMPLE
For n=7, p=17 and a(7) = floor(sqrt(17)) + floor(sqrt(34)) + floor(sqrt(51)) + floor(sqrt(68)) = 4+5+7+8 = 24.
MATHEMATICA
Table[p = Prime[n]; Sum[Floor[Sqrt[i*p]], {i, Floor[p/4]}], {n, 100}] (* T. D. Noe, Nov 13 2013 *)
PROG
(PARI) a(n) = p = prime(n); sum(i=1, p\4, sqrtint(i*p));
CROSSREFS
Sequence in context: A364313 A156435 A344048 * A298959 A162460 A187306
KEYWORD
nonn
AUTHOR
Michel Marcus, Nov 11 2013
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)