A354603 Numbers k such that sum of distinct primes dividing k is equal to the sum of proper divisors of k+1.

3, 7, 14, 31, 127, 206, 2974, 8191, 19358, 20490, 131071, 147454, 286122, 289650, 292332, 441276, 524287, 909498, 1207358, 1657968, 1782540, 2490042, 3368860, 9274806, 11367402, 14107852, 16776156, 18589386, 22910988, 24450316, 26867718, 28959606, 32674506, 33163372

Offset

1,1

Comments

Numbers k such that A008472(k) = A001065(k+1). All Mersenne primes are terms.

Links

Table of n, a(n) for n=1..34.

Example

Example:  14 is a term because A008472(14) = 2+7 = A001065(15) = 1+3+5.

Mathematica

Select[Range[19358], Sum[f, {f, Select[Divisors[#], PrimeQ]}]==DivisorSigma[1, #+1]-(#+1)&]

Crossrefs

Cf. A000668, A001065, A008472, A006145.

Sequence in context: A129629 A354463 A223136 * A089526 A261051 A231397

Adjacent sequences: A354600 A354601 A354602 * A354604 A354605 A354606

Keyword

nonn

Author

Metin Sariyar, Jul 08 2022

Extensions

More terms from Amiram Eldar, Jul 08 2022

Status

approved