A070904 a(1) = 1, a(n) is the smallest integer > a(n-1) such that the largest element in the simple continued fraction for S(n) = 1/a(1) + 1/a(2) + ... + 1/a(n) equals n^4.

1, 16, 20976, 50649, 51933, 86768, 99857, 442973, 547720, 1374279, 6529369, 15997726, 16615151, 18691278, 30371349, 43665242, 75220431

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Example

The continued fraction for S(5) = 1 + 1/16 + 1/20976 + 1/50649 + 1/51933 is [1, 15, 1, 44, 7, 1, 1, 1, 1, 3, 2, 2, 3, 1, 6, 3, 1, 625, 2, 4] where the largest element is 625 = 5^4 and 51933 is the smallest integer > 50649 with this property.

Prog

(PARI) s=1; t=1; for(n=2, 17, s=s+1/t; while(abs(n^4-vecmax(contfrac(s+1/t)))>0, t++); print1(t, ", "))

Crossrefs

Cf. A070902, A070903.

Sequence in context: A017296 A217271 A168488 * A308309 A159427 A340590

Adjacent sequences: A070901 A070902 A070903 * A070905 A070906 A070907

Keyword

nonn,more

Author

Benoit Cloitre, May 19 2002

Extensions

a(11)-a(16) from Ryan Propper, Aug 06 2005

a(17) from Jinyuan Wang, Apr 05 2020

Status

approved