A109182 Numbers k such that the k-th and (k+1)-th primes have the same sum of squares of digits.

293, 2106, 2161, 2763, 3698, 3793, 3795, 3812, 3922, 3959, 3995, 4000, 4205, 4224, 4260, 4728, 4953, 5065, 5283, 5617, 5700, 5751, 5932, 6326, 6333, 6422, 6539, 6623, 7375, 7475, 7501, 7533, 7542, 8306, 8568, 8751, 8777, 8994, 9102, 9259, 9354, 9480

Offset

1,1

Comments

Most of the pairs of successive primes also have the same set of digits. Those with different sets of digits are in A109183; the first relative numbers k are 3795, 3995, 10234, 17125, 18134, 19322, 20979.

Links

Table of n, a(n) for n=1..42.

Example

prime(293)=1913, prime(294)=1931; both have the same sum of digits squared: 1^2 + 9^2 + 1^2 + 3^2 = 1^2 + 9^2 + 3^2 + 1^2 = 92.

Mathematica

SequencePosition[Table[Total[IntegerDigits[Prime[n]]^2], {n, 10000}], {x_, x_}][[All, 1]] (* Harvey P. Dale, Jul 21 2021 *)

Crossrefs

Cf. A109183.

Sequence in context: A217182 A109562 A023305 * A342874 A241047 A085502

Adjacent sequences: A109179 A109180 A109181 * A109183 A109184 A109185

Keyword

base,nonn

Author

Zak Seidov, Jun 21 2005

Status

approved