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 A074802 Number of numbers k <= n such that tau(k) = tau(k+1) where tau(x) = A000005(x) is the number of divisors of x. 0
 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 12, 12, 12, 12, 12, 12, 12, 13, 14 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,14 LINKS Table of n, a(n) for n=1..94. FORMULA Is a(n) asymptotic to c*n with c=0.1......? MATHEMATICA Accumulate[If[#[[1]]==#[[2]], 1, 0]&/@Partition[DivisorSigma[ 0, Range[ 100]], 2, 1]] (* Harvey P. Dale, Jan 27 2021 *) PROG (PARI) a(n)=sum(i=1, n, if(numdiv(i)-numdiv(i+1), 0, 1)) CROSSREFS Cf. A000005 (tau), A005237. Partial sums of A130638. Sequence in context: A276798 A067100 A296237 * A071804 A280953 A111894 Adjacent sequences: A074799 A074800 A074801 * A074803 A074804 A074805 KEYWORD easy,nonn AUTHOR Benoit Cloitre, Sep 08 2002 STATUS approved

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Last modified May 30 12:55 EDT 2023. Contains 363050 sequences. (Running on oeis4.)