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A225758 Runs of consecutive numbers with the same number and sum of divisors. 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No triple found up to 10^9.

LINKS

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

EXAMPLE

Sequence begins:

14, 15;

1334, 1335;

1634, 1635;

2685, 2686;

33998, 33999;

etc.

MATHEMATICA

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

CROSSREFS

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

Cf. A054004 (first term of every run).

Sequence in context: A041417 A041418 A042733 * A043663 A043703 A174214

Adjacent sequences:  A225755 A225756 A225757 * A225759 A225760 A225761

KEYWORD

nonn,easy

AUTHOR

Jean-François Alcover, May 15 2013

STATUS

approved

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Last modified October 21 16:50 EDT 2019. Contains 328302 sequences. (Running on oeis4.)