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A109725 Divide primes in groups with 2n+1 elements and add together. 4
2, 15, 83, 281, 679, 1367, 2461, 4005, 6223, 9017, 12755, 17281, 22967, 29597, 37793, 47229, 57993, 70957, 85343, 101777, 119469, 141079, 163313, 188201, 216203, 247203, 280897, 316551, 355905, 398825, 445509, 494953, 549737, 605711, 665185 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

First difference of A109724.

LINKS

Ray Chandler, Table of n, a(n) for n = 0..9999

FORMULA

a(n) = A109724(n+1) - A109724(n) = A007504((n+1)^2) - A007504(n^2).

MATHEMATICA

f[n_] := Sum[Prime[k], {k, n}]; Table[f[(n+1)^2] - f[n^2], {n, 0, 34}]

With[{nn=40}, Total/@TakeList[Prime[Range[nn^2]], Range[1, 2nn-1, 2]]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jan 05 2019 *)

CROSSREFS

Cf. A007504, A109722-A109726.

Sequence in context: A268735 A215705 A301566 * A057152 A002740 A178750

Adjacent sequences:  A109722 A109723 A109724 * A109726 A109727 A109728

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Aug 10 2005

EXTENSIONS

Edited and extended by Ray Chandler, Aug 11 2005

STATUS

approved

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Last modified October 18 01:04 EDT 2019. Contains 328135 sequences. (Running on oeis4.)