A132315 Sum of the non-fourth powers less than or equal to n.
0, 2, 5, 9, 14, 20, 27, 35, 44, 54, 65, 77, 90, 104, 119, 119, 136, 154, 173, 193, 214, 236, 259, 283, 308, 334, 361, 389, 418, 448, 479, 511, 544, 578, 613, 649, 686, 724, 763, 803, 844, 886, 929, 973, 1018, 1064, 1111, 1159, 1208, 1258, 1309, 1361, 1414, 1468
Offset: 1
Keywords
Examples
Let n=16. The sum of the non-quartic numbers <= 16 is 2+3+4+5+6+7+8+9+10+11+12+13+14+15 = 119, the 16th entry in the sequence.
Programs
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PARI
g4(n)=for(x=1,n,r=floor(x^(1/4));sum4=r^5/5+r^4/2+r^3/3-r/30;sn=x*(x+1)/2;print1(sn-sum4","))
Formula
Let r = floor(n^(1/4)). Then a(n) = n(n+1)/2 - (r^5/5+r^4/2+r^3/3-r/30).