A288021 Prime p1 of consecutive primes p1, p2, where p2 - p1 = 4, and p1, p2 are in different decades.

7, 19, 37, 67, 79, 97, 109, 127, 229, 277, 307, 349, 379, 397, 439, 457, 487, 499, 739, 757, 769, 859, 877, 907, 937, 967, 1009, 1087, 1279, 1297, 1429, 1447, 1489, 1549, 1567, 1579, 1597, 1609, 1867, 1999, 2137, 2239, 2269, 2347, 2377, 2389, 2437, 2539, 2617, 2659, 2689, 2707, 2749, 2797, 2857

Offset

1,1

Comments

The unit digits of the numbers in the sequence are 7's or 9's.

Links

Table of n, a(n) for n=1..55.

Example

7 is in this sequence since pair (7,11) is the first with difference 4 spanning a multiple of 10.

Mathematica

a288021[n_] := Map[Last, Select[Map[{NextPrime[#, 1], NextPrime[#, -1]}&, Range[10, n, 10]], First[#]-Last[#]==4&]]
a288021[3000] (* data *)

Crossrefs

Cf. A001359, A023201, A023203, A031924, A031925, A031928, A046117, A046132, A158277, A158861, A160370, A160440, A160500, A287049, A287050, A060229, A288022, A288024.

Sequence in context: A155323 A121091 A213489 * A155394 A155412 A155420

Adjacent sequences: A288018 A288019 A288020 * A288022 A288023 A288024

Keyword

nonn

Author

Hartmut F. W. Hoft, Jun 04 2017

Status

approved