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A071746 p(7n+5)/7 where p(k) denotes the k-th partition number. 1
1, 11, 70, 348, 1449, 5334, 17822, 55165, 160215, 441105, 1159752, 2929465, 7142275, 16873472, 38749850, 86737678, 189672868, 405991500, 852077072, 1756048833, 3558408287, 7098041203, 13951818365, 27047831797, 51760979985 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

One of the congruences related to the partition numbers stated by Ramanujan.

REFERENCES

Berndt and Rankin, "Ramanujan: letters and commentaries", AMS-LMS, History of mathematics, vol. 9, pp. 192-193.

FORMULA

a(n) = (1/7)*A000041(7n+5)

PROG

(PARI) a(n)=if(n<0, 0, n=7*n+5; polcoeff(1/eta(x+x*O(x^n)), n)/7)

(PARI) {a(n)=local(A, B); if(n<0, 0, A=x*O(x^n); B=eta(x^7+A); A=eta(x+A); polcoeff( B^3/A^4 +x*7*B^7/A^8, n))} /* Michael Somos Jan 01 2006 */

CROSSREFS

Cf. A017041, A071734, A076394.

Sequence in context: A169731 A099336 A173200 * A205812 A162568 A117047

Adjacent sequences:  A071743 A071744 A071745 * A071747 A071748 A071749

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 24 2002

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Last modified February 14 22:22 EST 2012. Contains 205678 sequences.