A068835 Start of first occurrence of just n consecutive primes with all even digits except the least significant digit.

2, 23, 41, 821, 4409, 2063, 224401, 8609, 20066003, 20628046223, 82260284069, 2248462002229, 224682444608243

Offset

1,1

Comments

If the least significant digit must be odd, then a(1) = 241.

a(14) > 2*10^15. [From Donovan Johnson, Sep 21 2010]

Links

Table of n, a(n) for n=1..13.

Example

a(8) = 8609: the 8 consecutive primes are 8609, 8623, 8627, 8629, 8641, 8647, 8663, 8669.

Mathematica

a = {0, 1, 1, 1}; Do[ If[ Union[ EvenQ[ Drop[ IntegerDigits[ Prime[n]], -1]]] == {True}, a = Append[a, 1], a = Append[a, 0]], {n, 5, 10^5}]; Do[k = 3; b = Table[1, {n}]; b = Insert[b, 0, {{1}, {-1}}]; While[k < 10^5 - n && Take[a, {k - 1, k + n}] != b, k++ ]; If[k < 10^5, Print[ Prime[k]], Print[0]], {n, 1, 8}]

Crossrefs

Sequence in context: A106736 A045392 A107374 * A156557 A002428 A325145

Adjacent sequences: A068832 A068833 A068834 * A068836 A068837 A068838

Keyword

more,nonn,base

Author

Amarnath Murthy, Mar 09 2002

Extensions

Edited and extended by Robert G. Wilson v, Apr 10 2002

a(9)-a(12) from Donovan Johnson, Sep 03 2008

a(13) from Donovan Johnson, Sep 21 2010

Status

approved