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 A059591 Squarefree part of n^2+1. 5
 1, 2, 5, 10, 17, 26, 37, 2, 65, 82, 101, 122, 145, 170, 197, 226, 257, 290, 13, 362, 401, 442, 485, 530, 577, 626, 677, 730, 785, 842, 901, 962, 41, 1090, 1157, 1226, 1297, 1370, 5, 1522, 1601, 2, 1765, 74, 1937, 2026, 2117, 2210, 2305, 2402, 2501, 2602 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Related to period-1 continued fractions [z,z,z,...]. LINKS Enrique PĂ©rez Herrero, Table of n, a(n) for n = 0..5000 FORMULA a(n) = A007913(n^2+1). a(n)*A059592(n)^2 = n^2+1. EXAMPLE a(7)=2 since 7^2+1 = 50 = 25*2 = (5^2)*2. MAPLE A:= proc(n) local F; F:= select(t -> t[2]::odd, ifactors(n^2+1)[2]); mul(t[1], t=F) end proc: map(A, [\$0..100]); # Robert Israel, Jun 18 2015 MATHEMATICA Table[Times @@ Flatten[Table[#1, {#2}] & @@@ Select[FactorInteger[n^2 + 1], OddQ@ Last@ # &]], {n, 120}] (* Michael De Vlieger, Jun 19 2015 *) PROG (PARI) a(n) = core(n^2+1); \\ Michel Marcus, Jun 18 2015 CROSSREFS Cf. A007913, A059592, A000188. Sequence in context: A340045 A100292 A078325 * A082607 A303372 A159547 Adjacent sequences:  A059588 A059589 A059590 * A059592 A059593 A059594 KEYWORD easy,nonn AUTHOR Marc LeBrun, Jan 25 2001 STATUS approved

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Last modified August 2 12:00 EDT 2021. Contains 346422 sequences. (Running on oeis4.)