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A288021 Prime p1 of consecutive primes p1, p2, where p2 - p1 = 4, and p1, p2 are in different decades. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 29 03:33 EDT 2022. Contains 357082 sequences. (Running on oeis4.)