A115177 Positive numbers that are not the sum of a triangular number, a nonnegative cube and a positive Fibonacci number.

690, 861, 915, 929, 1201, 1319, 1451, 1538, 1578, 1803, 1965, 2104, 2427, 2532, 2573, 2671, 2680, 2734, 2769, 2965, 3001, 3154, 3175, 3255, 3259, 3260, 3336, 3434, 3476, 3603, 3628, 3670, 3805, 3840, 3847, 3898, 3903, 3953, 4050, 4128

Offset: 1

Author

Giovanni Resta, Jan 15 2006

Keywords

• nonn

Comments

There are 225943534 such numbers up to 10^9, the last one in this range being 999999997.

Links

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

Crossrefs

Cf. A115171, A115172, A115173, A115174, A115175, A115176.

Programs

Maple

N:=10000: # to get all terms <= N
T:= [seq(t*(t+1)/2, t=0..floor((sqrt(1+8*N)-1)/2))]:
C:= [seq(t^3, t=0..floor(N^(1/3)))]:
F:= [seq(combinat:-fibonacci(t), t=1..floor(log[(sqrt(5)+1)/2](N*sqrt(5))))]:
CF:= select(`<=`,{seq(seq(c+f, c=C),f=F)},N):
sort(convert({$1..N} minus {seq(seq(t+cf,t=T),cf=CF)}, list)); # Robert Israel, Mar 08 2018

Extensions

Name clarified by Altug Alkan, May 02 2016