A059974 a(n)=a(p)+a(q) where p and q are the two primes less than n and closest to n; with a(1)=1, a(2)=1, a(3) = 1.

1, 1, 1, 2, 2, 3, 3, 5, 5, 5, 5, 8, 8, 13, 13, 13, 13, 21, 21, 34, 34, 34, 34, 55, 55, 55, 55, 55, 55, 89, 89, 144, 144, 144, 144, 144, 144, 233, 233, 233, 233, 377, 377, 610, 610, 610, 610, 987, 987, 987, 987, 987, 987, 1597, 1597, 1597, 1597, 1597, 1597, 2584

Offset

1,4

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(4)=a(3)+a(2)=1+1=2

Maple

with(numtheory): a := proc(n) option remember: if n <= 3 and n >=1 then RETURN(1) fi: a(prevprime(n))+ a(prevprime(prevprime(n))): end: for n from 1 to 150 do printf(`%d, `, a(n)) od:

Crossrefs

Sequence in context: A033302 A072729 A057872 * A045767 A108221 A169682

Adjacent sequences: A059971 A059972 A059973 * A059975 A059976 A059977

Keyword

easy,nonn

Author

Brian Wallace (wallacebrianedward(AT)yahoo.co.uk), Mar 05 2001

Extensions

More terms from James A. Sellers, Mar 15 2001

Name edited by Robert Israel, Feb 22 2023

Status

approved