A054681 Start of a run of consecutive primes of length n each ending with the same digit.

2, 139, 1627, 18839, 123229, 776257, 3873011, 23884639, 36539311, 196943081, 452942827, 73712513057, 154351758091, 154351758091, 4010803176619, 6987191424553, 71894236537009, 196948379177587, 253931039382791

Offset

1,1

Comments

n consecutive primes differ by a multiple of 10 starting at a(n).

n consecutive primes that are congruent mod 10, i.e., they are not necessarily in arithmetic progression.

Links

Table of n, a(n) for n=1..19.

J. K. Andersen, Consecutive Congruent Primes.

William F. Sindelar, Mark Underwood, Mikael Klasson, Gaps Between Consecutive Odds not Divisible by 3, digest of 5 messages in primenumbers Yahoo group, Jun 27 - Jun 29, 2003. [Cached copy]

Mark Underwood's Problem posed on the "PrimeNumbers" yahoogroup (2003)

Example

a(2)=139 because 139 and 149 are the first consecutive primes to share a terminal digit.

Prog

(PARI) i=1; s=0; d=0; l=0; forprime(p=1, 500000, if(p%10==d, l++, if(l>=i, print(s); i++); s=p; d=p%10; l=1)) \\ (Carmody)

Crossrefs

Sequence in context: A212715 A329594 A084560 * A152509 A265462 A094482

Adjacent sequences: A054678 A054679 A054680 * A054682 A054683 A054684

Keyword

nonn,base

Author

Jeff Burch, Apr 18 2000

Extensions

More terms from Phil Carmody, Jun 27 2003

Further from Jens Kruse Andersen, Jun 03 2006

a(17)-a(19) from Giovanni Resta, Aug 01 2013

Status

approved