A182781 Number of n-digit terms in A048398.

4, 4, 2, 1, 12, 20, 35, 28, 80, 114, 211, 228, 736, 1214, 2101, 2536, 7799, 13830, 22107, 27265, 82611, 144324, 259260, 354029, 901774, 1651718, 2913981, 3913728, 11048656, 19782855, 33483206, 49533124

Offset: 1

Author

Zak Seidov, Feb 01 2011

Keywords

• nonn
• base
• more

Comments

Also, number of n-digit primes in A033075.

Appears to be strictly increasing for n >= 8. - Chai Wah Wu, May 31 2017

Crossrefs

Cf. A033075, A048398.

Programs

Maple

A182781aux := proc(Lhig,n) local lsb,a ; if n = 0 then if isprime(Lhig) then    1; else 0; end if; else a := 0 ; lsb := Lhig mod 10 ; if lsb > 0 then a := a + procname(10*Lhig+lsb-1,n-1) ; end if; if lsb < 9 then a := a + procname(10*Lhig+lsb+1,n-1) ; end if; a; end if; end proc:
A182781 := proc(n) if n = 1 then 4; else a := 0 ; for l from 1 to 9 do a := a + A182781aux(l,n-1) ; end do: a ; end if; end proc: # R. J. Mathar, Feb 01 2011

Extensions

a(22)-a(24) from Chai Wah Wu, May 31 2017

a(25)-a(32) from Chai Wah Wu, Jun 05 2017