A078835 Sum of the divisors of the average of consecutive odd primes.

7, 12, 13, 28, 24, 39, 32, 42, 72, 54, 56, 96, 78, 93, 120, 168, 127, 96, 195, 140, 121, 132, 128, 156, 216, 192, 280, 152, 360, 176, 204, 288, 403, 372, 288, 378, 288, 324, 372, 546, 384, 508, 336, 468, 252, 256, 403, 560, 384, 420, 744, 504, 384, 588, 480

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Formula

a(n) = A000203(A024675(n)). - Omar E. Pol, Dec 08 2019

Example

The first pair of consecutive odd primes is 3,5, with average = 4 and sigma(4) = 7. Hence a(1) = 7. The second pair of consecutive odd primes is 5,7, with average = 6 and sigma(6) = 12, so a(2) = 12.

Mathematica

Table[DivisorSigma[1, (Prime[i] + Prime[i + 1])/2], {i, 2, 101}]
DivisorSigma[1, Mean[#]]&/@Partition[Prime[Range[2, 60]], 2, 1] (* Harvey P. Dale, Dec 07 2013 *)

Crossrefs

Cf. A000203, A024675.

Sequence in context: A205807 A075696 A061120 * A173417 A031021 A353444

Adjacent sequences: A078832 A078833 A078834 * A078836 A078837 A078838

Keyword

easy,nonn

Author

Joseph L. Pe, Jan 11 2003

Status

approved