OFFSET
1,2
COMMENTS
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Charles R Greathouse IV, PARI/GP script to find terms of this sequence
MATHEMATICA
mod4PrimeSignature[n_] := {fi = FactorInteger[n]; If[OddQ[n], 0, fi[[1, 2]]], Select[fi, Mod[#[[1]], 4] == 3 &][[All, 2]]//Sort, Select[fi, Mod[#[[1]], 4] == 1 &][[All, 2]]}; A097751[n_] := Catch[For[k = 2, True, k++, If[ mod4PrimeSignature[k] == mod4PrimeSignature[n], Throw[k]]]]; A097751[1] = 1; Select[ Range[243], A097751[#] == # &] (* Jean-François Alcover, Jan 10 2013 *)
PROG
(PARI) is(n)=n>>=valuation(n, 2); my(e3=valuation(n, 3), e1=valuation(n, 5), e); n/=3^e3 * 5^e1; forprime(p=7, , e=valuation(n, p); if(p%4==1, if(e1<e, return(0)); e1=e, if(e3<e, return(0)); e3=e); if(e, n/=p^e, if(e1==0 && e3==0, return(n==1)))) \\ Charles R Greathouse IV, Dec 10 2016
(PARI) See Greathouse link.
CROSSREFS
KEYWORD
nonn
AUTHOR
Ray Chandler, Aug 26 2004
STATUS
approved