A225758 Runs of consecutive numbers with the same number and sum of divisors.

14, 15, 1334, 1335, 1634, 1635, 2685, 2686, 33998, 33999, 42818, 42819, 64665, 64666, 84134, 84135, 109214, 109215, 122073, 122074, 166934, 166935, 289454, 289455, 383594, 383595, 440013, 440014, 544334, 544335, 605985, 605986, 649154, 649155, 655005, 655006

Offset: 1

Author

Jean-François Alcover, May 15 2013

Keywords

• nonn
• easy

Comments

No triple found up to 10^9.

Examples

			Sequence begins:
14, 15;
1334, 1335;
1634, 1635;
2685, 2686;
33998, 33999;
etc.
		

Links

• Donovan Johnson, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A225756 (same number of divisors), A225757 (same sum of divisors).

Cf. A054004 (first term of every run).

Programs

Mathematica

sel = Select[Range[1000000], DivisorSigma[0, #] == DivisorSigma[0, #+1] && DivisorSigma[1, #] == DivisorSigma[1, #+1] &]; Union[sel, sel+1]