A139246 Triangle read by rows: row n lists the proper divisors of n-th perfect number A000396(n).

1, 2, 3, 1, 2, 4, 7, 14, 1, 2, 4, 8, 16, 31, 62, 124, 248, 1, 2, 4, 8, 16, 32, 64, 127, 254, 508, 1016, 2032, 4064, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8191, 16382, 32764, 65528, 131056, 262112, 524224, 1048448, 2096896, 4193792, 8387584, 16775168, 1

Offset

1,2

Comments

Rows n has A133033(n) terms.

The n-th row sum is the n-th perfect number A000396(n).

Links

Table of n, a(n) for n=1..56.

Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos".

Example

Triangle begins:
1, 2, 3
1, 2, 4, 7, 14
1, 2, 4, 8, 16, 31, 62, 124, 248

Crossrefs

Cf. A000396, A018254, A018487, A133024, A133025, A133031, A133033, A135652, A135653, A135654, A135655, A139247.

Sequence in context: A081536 A297497 A152736 * A187247 A131227 A190257

Adjacent sequences: A139243 A139244 A139245 * A139247 A139248 A139249

Keyword

nonn,tabf

Author

Omar E. Pol, Apr 22 2008, corrected Apr 25 2008

Status

approved