A276714 Numbers n such that n and n+3 have the same number and sum of divisors (A000005 and A000203).

42677635, 276742235, 6439057062, 7512673242, 43592652562, 48847956255, 48880963215, 55018687182, 60184185702, 91484515395, 100774916235, 101926379835, 111886551315, 122388340095, 133012188855, 137978601142, 247631352255, 263171068875, 293467635615, 305946896255

Offset

1,1

Comments

Intersection of A015861 and A276713.

Also numbers n such that A229335(n) = A229335(n+3).

Links

Martin Ehrenstein, Table of n, a(n) for n = 1..30

Example

42677635 is in sequence because tau(42677635) = tau(42677638) = 32 and sigma(42677635) = sigma(42677638) = 68769792.

Prog

(Magma) [n: n in [A015861(k)] | NumberOfDivisors(n) eq  NumberOfDivisors(n+3) and SumOfDivisors(n) eq  SumOfDivisors(n+3)]

Crossrefs

Cf. A015861, A229335, A276713, A276715.

Cf. Similar sequences with numbers n such that n and n+k have the same number and sum of divisors for k=1: A054004, for k=2: A229254.

Sequence in context: A213737 A254091 A254098 * A187963 A028520 A288843

Adjacent sequences: A276711 A276712 A276713 * A276715 A276716 A276717

Keyword

nonn

Author

Jaroslav Krizek, Sep 16 2016

Extensions

More terms from Martin Ehrenstein, Jul 12 2024

Status

approved