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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

Amiram Eldar, Table of n, a(n) for n = 1..1000

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: A193874 A254939 A038688 * A144298 A072109 A045490

Adjacent sequences:  A076827 A076828 A076829 * A076831 A076832 A076833

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 08:13 EST 2020. Contains 332201 sequences. (Running on oeis4.)