A246852 Numbers n such that sigma(n+2) - sigma(n) = n + 2.

1, 2, 22, 14926, 31048, 69106, 246262, 5860168, 307164670, 881198662, 1489455646, 2386555630, 8225563702, 14311679062, 111494234182, 154357775302, 299004519622, 870455062822, 970388922262, 991817878342, 1677028870822, 1782783762502, 1830446935222

Offset: 1

Author

Jaroslav Krizek, Sep 05 2014

Keywords

• nonn

Comments

Also numbers n such that A001065(n+2) = A000203(n). - Michel Marcus, Sep 06 2014

Examples

			Number 22 is in sequence because sigma(22+2) - sigma(22) = 60 - 36 = 24 = 22 + 2.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..33 (terms < 10^13)

Crossrefs

Cf. A000203, A067816, A246851, A246853, A246854, A246855.

Programs

Magma

[n:n in[1..10^7] | SumOfDivisors(n+2)-SumOfDivisors(n) eq n+2]

Mathematica

Select[Range[6*10^6], DivisorSigma[1, # + 2] - DivisorSigma[1, #] == # + 2 &] (* Jake L Lande, Jun 30 2024 *)

PARI

for(n=1,10^7,if(sigma(n+2)-sigma(n)==n+2,print1(n,", "))) \\ Derek Orr, Sep 05 2014

Extensions

a(9)-a(14) from Hiroaki Yamanouchi, Sep 10 2014

a(15)-a(23) from Giovanni Resta, Jul 13 2015