A102359 a(n) = sigma((4^n - 1)/3), where sigma(n) is the sum of positive divisors of n.

1, 6, 32, 108, 384, 2688, 5632, 27864, 153920, 499968, 1477440, 11708928, 22380544, 115568640, 620101632, 1826150832, 5726797824, 54044390400, 91626668032, 555102471168, 2352412508160, 7458459886080, 23955459951744, 199536712962048, 425355918188544, 1849167560835072

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..603

Formula

a(n) = A000203(A002450(n)). - Amiram Eldar, Feb 21 2020

Prog

(PARI) a(n) = sigma((4^n - 1)/3); \\ Michel Marcus, Feb 21 2020

Crossrefs

Cf. A000203, A002450.

Sequence in context: A288961 A090382 A360839 * A000397 A200765 A239573

Adjacent sequences: A102356 A102357 A102358 * A102360 A102361 A102362

Keyword

nonn

Author

Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Feb 22 2005

Extensions

More terms from Amiram Eldar, Feb 21 2020

Status

approved