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

1,1

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

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

Crossrefs

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

Sequence in context: A078877 A204145 A284284 * A263114 A214335 A060054

Adjacent sequences: A115174 A115175 A115176 * A115178 A115179 A115180

Keyword

nonn

Author

Giovanni Resta, Jan 15 2006

Extensions

Name clarified by Altug Alkan, May 02 2016

Status

approved