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A072984
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Least k such that prime(n) appears in the factorization of A001008(k) (the numerator of the k-th harmonic number).
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9
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2, 4, 6, 3, 12, 16, 18, 22, 13, 30, 17, 40, 13, 46, 22, 58, 10, 66, 70, 72, 78, 82, 88, 11, 100, 102, 106, 25, 112, 126, 130, 5, 138, 148, 150, 156, 162, 166, 71, 178, 180, 190, 192, 196, 38, 210, 222, 22, 228, 232, 238, 240, 250, 66, 262, 33, 58, 276, 280, 282
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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COMMENTS
| a(n)<=n for n =2,5,14,18,25,29,33,46,49,...
For p = prime(n), Boyd defines J_p to be the set of numbers k such that p divides A001008(k). This sequence gives the smallest elements of J_p. The largest elements of J_p are given by A177734. The sizes of J_p are given by A092103.
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REFERENCES
| A. Eswarathasan and E. Levine, p-integral harmonic sums, Discrete Math. 91 (1991), 249-257.
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LINKS
| T. D. Noe, Table of n, a(n) for n = 2..1000
David W. Boyd, A p-adic study of the partial sums of the harmonic series, Experimental Math., Vol. 3 (1994), No. 4, 287-302.
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PROG
| (PARI) a(n)=if(n<0, 0, s=1; while(numerator(sum(k=1, s, 1/k))%prime(n)>0, s++); s)
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CROSSREFS
| Cf. A092101 (harmonic primes), A092102 (non-harmonic primes), A092103 (size of Jp).
Sequence in context: A108236 A002849 A163234 * A018841 A138125 A098793
Adjacent sequences: A072981 A072982 A072983 * A072985 A072986 A072987
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KEYWORD
| easy,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 21 2002
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