A288021 - OEIS

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

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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 *)