A076538 Numerators a(n) of fractions slowly converging to e: let a(1) = 0, b(n) = n - a(n); if (a(n) + 1) / b(n) < e then a(n+1) = a(n) + 1, else a(n+1)= a(n).

0, 1, 2, 2, 3, 4, 5, 5, 6, 7, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 16, 16, 17, 18, 19, 19, 20, 21, 21, 22, 23, 24, 24, 25, 26, 27, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37, 38, 38, 39, 40, 40, 41, 42, 43, 43, 44, 45, 46, 46, 47, 48, 48, 49, 50, 51, 51, 52, 53

Offset

1,3

Comments

a(n) + b(n) = n and as n -> +infinity, a(n) / b(n) converges to e. For all n, a(n) / b(n) < e.

Links

Table of n, a(n) for n=1..73.

Formula

a(1) = 0. b(n) = n - a(n). If (a(n) + 1) / b(n) < e, then a(n+1) = a(n) + 1, else a(n+1) = a(n).

a(n) = floor(n*exp(1)/(exp(1)+1)). - Vladeta Jovovic, Oct 04 2003

Example

a(6)= 4 so b(6) = 6 - 4 = 2. a(7) = 5 because (a(6) + 1) / b(6) = 5/2 which is < e. So b(7) = 7 - 5 = 2. a(8) = 5 because (a(7) + 1) / b(7) = 6/2 which is not < e.

Prog

(PARI) a(n)=local(t); if(n<2, 0, t=0; for(k=0, n-1, if(1+t<exp(1)*(k-t), t++)); t)

Crossrefs

Cf. A074840.

Partial sums of A144610.

Sequence in context: A257175 A210357 A057359 * A138466 A247784 A249243

Adjacent sequences: A076535 A076536 A076537 * A076539 A076540 A076541

Keyword

easy,frac,nonn

Author

Robert A. Stump (bee_ess107(AT)msn.com), Oct 18 2002

Status

approved