A289895 Numbers that are the sum of distinct square pyramidal numbers (A000330).

0, 1, 5, 6, 14, 15, 19, 20, 30, 31, 35, 36, 44, 45, 49, 50, 55, 56, 60, 61, 69, 70, 74, 75, 85, 86, 90, 91, 92, 96, 97, 99, 100, 104, 105, 106, 110, 111, 121, 122, 126, 127, 135, 136, 140, 141, 145, 146, 147, 151, 152, 154, 155, 159, 160, 161, 165, 166, 170, 171, 175, 176, 177, 181, 182, 184, 185, 189, 190, 191, 195, 196, 200

Offset: 1

Author

Ilya Gutkovskiy, Jul 14 2017

Keywords

• nonn

Comments

It appears that 1528 is the largest of 306 positive integers not in this sequence.

Examples

			20 is in the sequence because 20 = 1 + 5 + 14 = 1^2 + 1^2 + 2^2 + 1^2 + 2^2 + 3^2.
		

Links

• Index entries for sequences related to sums of squares
• Index to sequences related to pyramidal numbers

Crossrefs

Cf. A000330, A003995.

Programs

Mathematica

max = 200; f[x_] := Product[1 + x^(k (k + 1) (2 k + 1)/6), {k, 1, 10}]; Exponent[#, x] & /@ List @@ Normal[Series[f[x], {x, 0, max}]]

Formula

Exponents in expansion of Product_{k>=1} (1 + x^(k*(k+1)*(2*k+1)/6)).