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A076830 Least square s such that A078142(s) is equal to the n-th prime. 1
4, 36, 121, 484, 2809, 11236, 6889, 27556, 29929, 51529, 85849, 744769, 196249, 734449, 727609, 942841, 1203409, 4813636, 1510441, 1885129, 7540516, 8048569, 4932841, 4108729, 7946761, 12243001, 18088009, 10608049, 12187081, 10569001 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(1) = 4 since 4 = 2^2 is the least square s such that A078142(s) = 2, the first prime.
a(2) = 36 since 36 = 6^2 is the least square s such that A078142(s) = 3, the second prime.
MATHEMATICA
s[n_] := Total[Ceiling[Sqrt[(p = FactorInteger[n][[;; , 1]])]]^2 - p]; m = 30; seq = Table[0, {m}]; c = 0; k = 1; While[c < m, n = s[k^2]; If[PrimeQ[n] && (i = PrimePi[n]) <= m && seq[[i]] == 0, c++; seq[[i]] = k^2]; k++]; seq (* Amiram Eldar, Dec 11 2019 *)
CROSSREFS
Cf. A078142.
Sequence in context: A254939 A038688 A362751 * A144298 A072109 A045490
KEYWORD
nonn
AUTHOR
Jason Earls, Nov 21 2002
EXTENSIONS
Name edited by Amiram Eldar, Dec 11 2019
STATUS
approved

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Last modified February 24 12:51 EST 2024. Contains 370303 sequences. (Running on oeis4.)