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A161183
Terms which occur at least twice in A161182.
0
1, 9, 16, 25, 53, 78, 82, 89, 115, 120, 130, 152, 161, 178, 196, 224, 233, 235, 250, 256, 265, 286, 291, 300, 301, 314, 315, 325, 347, 357, 360, 368, 381, 391, 397, 419, 428, 430, 456, 468, 479, 483, 484, 494, 495, 512, 528, 570, 577, 589, 591, 608, 610, 620
OFFSET
1,2
COMMENTS
A161182 is not monotonic, so some terms (like 89) listed here are not direct neighbors in A161182. - R. J. Mathar, Jun 22 2009
MAPLE
A038107 := proc(n) numtheory[pi]( n^2) ; end: A078435 := proc(n) n^2-A038107(n) ; end: A161182 := proc(n) A078435(n)-A078435(n-1) ; end: L := [] ; for n from 1 to 1200 do L := [op(L), A161182(n)] ; od: read("transforms3") ; L := sort(L) ; L := LISTDUPL(L, 0) ; # R. J. Mathar, Jun 22 2009
MATHEMATICA
f[n_] := 2n - 1 - PrimePi[n^2] + PrimePi[(n-1)^2];
Select[Split[Array[f, 1000]//Sort], Length[#] >= 2&][[All, 1]]
(* Jean-François Alcover, Mar 07 2023 *)
CROSSREFS
Sequence in context: A092941 A075393 A336449 * A183345 A303873 A257496
KEYWORD
easy,nonn
AUTHOR
Daniel Tisdale, Jun 05 2009
EXTENSIONS
Edited by N. J. A. Sloane, Jun 07 2009
Missing numbers added by R. J. Mathar, Jun 22 2009
STATUS
approved