cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A295907 a(n) = SumXOR_{k=1..n} A296099(k), where SumXOR is the analog of summation under the binary XOR operation.

Original entry on oeis.org

1, 2, 0, 4, 15, 6, 0, 8, 27, 30, 11, 12, 0, 14, 30, 0, 17, 54, 57, 20, 0, 22, 46, 0, 25, 78, 81, 112, 58, 30, 62, 0, 66, 34, 0, 72, 37, 0, 78, 120, 82, 126, 86, 0, 90, 46, 94, 0, 49, 100, 0, 52, 159, 162, 220, 224, 171, 232, 177, 240, 183, 186, 252, 128, 0
Offset: 1

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Author

Rémy Sigrist, Dec 05 2017

Keywords

Comments

For any n > 0, a(n) is divisible by n.
For any n > 0, if a(n) = 0, then A296099(n+1) is a multiple of n+1.

Examples

			a(3) = A296099(1) XOR A296099(2) XOR A296099(3) = 1 XOR 3 XOR 2 = 0.
		

Crossrefs

Cf. A296099.

Programs

  • PARI
    s = 0; x = 0; for (n=1, 65, for (k=1, oo, if (!bittest(s,k) && (xx=bitxor(x,k))%n==0, x = xx; s += 2^k; print1 (x ", "); break)))