cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A307890 Prime centuries with at least one prime year in each decade and exactly one prime year in decades 1 to 8.

Original entry on oeis.org

3677, 4073, 16447, 118463, 211217, 357131, 368153, 582017, 932413, 1172777, 1239443, 2284027, 2421473, 3900931, 4943777, 5046053, 6850463, 6966059, 8046347, 10448783, 11548777, 12849937, 15198811, 16031237, 17315087, 19443679, 20075687, 20434811, 20462861, 20614667
Offset: 1

Views

Author

Zak Seidov, Feb 27 2009

Keywords

Comments

In other words, prime numbers p such that there are ten consecutive primes between p*100-100 and p*100, each of them in a different decade. (The P-div-10s are all different.) - Don Reble, May 02 2019

Examples

			4073 is in the sequence, representing the prime sequence 407203, 407207, 407219, 407221, 407233, 407249, 407257, 407263, 407273, 407287, 407291, 407299, with 2 primes in decades 0 and 9, and 1 prime in decades 1 to 8. - _R. J. Mathar_, May 03 2019
		

Crossrefs

Cf. A156115, super set of the primes in A103608.

Programs

  • Maple
    isA307890 := proc(n)
        local p, dec ;
        if not isprime(n) then
            false;
        else
            p := 100*(n-1) ;
            p := prevprime(p+10) ;
            for dec from 0 to 9 do
                if modp(floor(p/10), 10) <> dec then
                    return false;
                end if;
                p := nextprime(p) ;
            end do:
            true ;
        end if;
    end proc:
    for i from 1 do
        p := ithprime(i) ;
        if isA307890(p) then
            printf("%d, \n", p) ;
        end if;
    end do: # R. J. Mathar, May 03 2019