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 A263085 Partial sums of A099774 (A099774(n) = number of divisors of n-th odd number). 5
 1, 3, 5, 7, 10, 12, 14, 18, 20, 22, 26, 28, 31, 35, 37, 39, 43, 47, 49, 53, 55, 57, 63, 65, 68, 72, 74, 78, 82, 84, 86, 92, 96, 98, 102, 104, 106, 112, 116, 118, 123, 125, 129, 133, 135, 139, 143, 147, 149, 155, 157, 159, 167, 169, 171, 175, 177, 181, 187, 191, 194, 198 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10082 FORMULA a(1) = 1; for n > 1, a(n) = A000005((2*n)-1) + a(n-1). [Where A000005(k) gives the number of divisors of k.] Other identities. For all n >= 1: a(n) = A263086(n) - A263084(n). MATHEMATICA FoldList[DivisorSigma[0, 2*#2-1]+#1&, 1, Range[2, 62]] (* Ivan N. Ianakiev, Oct 24 2015 *) Accumulate[Table[DivisorSigma[0, 2*n-1], {n, 1, 100}]] (* Vaclav Kotesovec, Jan 14 2019 *) PROG (Scheme, with memoization-macro definec) (definec (A263085 n) (if (= 1 n) (A099774 n) (+ (A099774 n) (A263085 (- n 1))))) (PARI) lista(nn) = {s = 0; forstep (n=1, nn, 2, s += numdiv(n); print1(s, ", "); ); } \\ Michel Marcus, Oct 12 2015 CROSSREFS Cf. A000005, A006218, A099774, A263086. Sequence in context: A327213 A047390 A184653 * A206334 A184741 A020959 Adjacent sequences:  A263082 A263083 A263084 * A263086 A263087 A263088 KEYWORD nonn AUTHOR Antti Karttunen, Oct 12 2015 STATUS approved

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Last modified September 20 21:03 EDT 2019. Contains 327247 sequences. (Running on oeis4.)