login
A288022
Prime p1 of consecutive primes p1, p2, where p2 - p1 = 6, and p1, p2 are in different decades.
4
47, 157, 167, 257, 367, 557, 587, 607, 647, 677, 727, 947, 977, 1097, 1117, 1187, 1217, 1367, 1657, 1747, 1777, 1907, 1987, 2207, 2287, 2417, 2467, 2677, 2837, 2897, 2957, 3307, 3407, 3607, 3617, 3637, 3727, 3797, 4007, 4357, 4457, 4507, 4597, 4657, 4937, 4987
OFFSET
1,1
COMMENTS
The unit digits of the numbers in the sequence are 7's.
Number of terms < 10^k: 0, 0, 1, 13, 81, 565, 4027, 30422, 237715, ... - Muniru A Asiru, Jan 09 2018
LINKS
EXAMPLE
47 is in the sequence since pair (47,53) is the first with difference 6 spanning a multiple of 10.
MAPLE
for n from 1 to 2000 do if [ithprime(n+1)-ithprime(n), ithprime(n) mod 5] = [6, 2] then print(ithprime(n)); fi; od; # Muniru A Asiru, Jan 19 2018
MATHEMATICA
a288022[n_] := Map[Last, Select[Map[{NextPrime[#, 1], NextPrime[#, -1]}&, Range[10, n, 10]], First[#]-Last[#]==6&]]
a288022[3000] (* data *)
PROG
(GAP)
P:=Filtered([1..20000], IsPrime);
P1:=List(Filtered(Filtered(List([1..Length(P)-1], n->[P[n], P[n+1]]), i->i[2]-i[1]=6), j->j[1] mod 5=2), k->k[1]); # Muniru A Asiru, Jul 08 2017
KEYWORD
nonn
AUTHOR
Hartmut F. W. Hoft, Jun 04 2017
STATUS
approved