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 A063943 Numbers n such that phi(n) = sigma(n) - sigma(n+1). 1
 170, 518, 15416, 16472, 21584, 52744, 140864, 187736, 196318, 318626, 354118, 639286, 828814, 942326, 1333172, 1604018, 3301024, 5240458, 6490678, 7552264, 8040166, 8321326, 9790430, 12237950, 12461834, 14818438, 19012455, 20392318, 22625158, 29201984 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harry J. Smith and Donovan Johnson, Table of n, a(n) for n = 1..100 (first 39 terms from Harry J. Smith) PROG (PARI) for(n=1, 30000000, if(eulerphi(n)==sigma(n)-sigma(n+1), print1(n, ", "))) (PARI) { n=-1; t=0; for (m=1, 10^9, s=t; t=sigma(m + 1); if (eulerphi(m)==s - t, write("b063943.txt", n++, " ", m); if (n==38, break)) ) } [Harry J. Smith, Sep 03 2009] CROSSREFS Sequence in context: A043344 A045153 A045041 * A364905 A362561 A045089 Adjacent sequences: A063940 A063941 A063942 * A063944 A063945 A063946 KEYWORD nonn AUTHOR Jason Earls, Sep 01 2001 EXTENSIONS More terms from Rick L. Shepherd, Apr 06 2002 Offset corrected by Donovan Johnson, Feb 25 2013 STATUS approved

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Last modified August 9 02:38 EDT 2024. Contains 375024 sequences. (Running on oeis4.)