A115160 Numbers that are not the sum of two triangular numbers and a fourth power.

33, 63, 75, 125, 365, 489, 492, 684, 693, 723, 954, 1043, 1185, 1505, 1623, 1629, 1736, 1775, 1899, 1904, 1925, 2015, 2051, 2679, 2883, 3534, 3774, 3936, 4332, 4461, 4739, 4923, 5445, 5721, 5847, 6285, 6348, 6474, 6783, 7034, 7478, 8604, 9576, 9686, 9863

Offset

1,1

Comments

There are 88 such numbers up to 2*10^9, the last one in this range being 1945428.

Links

David W. Wilson, Table of n, a(n) for n = 1..88

Prog

(PARI) sumset_lim(a, b, lim)=my(v=[], u, t); if(a==b, for(i=1, #a, u=List(); for(j=i, #b, t=a[i]+b[j]; if(t>lim, break); listput(u, t)); v=vecsort(concat(v, Vec(u)), , 8)), for(i=1, #a, u=List(); for(j=1, #b, t=a[i]+b[j]; if(t>lim, break); listput(u, t)); v=vecsort(concat(v, Vec(u)), , 8))); v
makev(lim)=my(n=floor(sqrt(2*lim)-1/2), v); sumset_lim(v=vector(n, k, k*(k-1)/2), v, lim)
is(n)=for(i=1, #v, if(ispower(n-v[i], 4), return(0)); if(v[i]>n, return(1)))
v=makev(1e5);
for(n=1, 1e5, if(is(n), print1(n", "))) \\ Charles R Greathouse IV, Aug 17 2011

Crossrefs

Cf. A022552, A014158, A115159, A115161, A115162, A115163.

Sequence in context: A140156 A154600 A100593 * A053179 A183347 A116350

Adjacent sequences: A115157 A115158 A115159 * A115161 A115162 A115163

Keyword

nonn

Author

Giovanni Resta, Jan 15 2006

Status

approved