A145387 Natural numbers n such that n-1 and n+1 are prime, also (sum of digits) + 1 and (sum of digits) - 1 is prime.

4, 6, 42, 60, 138, 150, 192, 198, 228, 240, 282, 312, 420, 462, 570, 600, 642, 660, 822, 828, 882, 1032, 1050, 1092, 1230, 1278, 1290, 1302, 1320, 1452, 1722, 1872, 2028, 2082, 2088, 2112, 2130, 2268, 2310, 2550, 2592, 2712, 2730, 2790, 2802, 2970, 3120

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Maple

isA014574 := proc(n) RETURN( isprime(n-1) and isprime(n+1)) ; end: A007953 := proc(n) add(i, i=convert(n, base, 10) ); end: isA145387 := proc(n) RETURN(isA014574(n) and isprime( A007953(n)+1) and isprime( A007953(n)-1) ) ; end: for n from 1 to 3400 do if isA145387(n) then printf("%d, ", n) ; fi; od: # R. J. Mathar, Nov 18 2008

Mathematica

Select[Range[3200], AllTrue[Flatten[{#+{1, -1}, Total[IntegerDigits[#]]+{1, -1}}], PrimeQ]&] (* Harvey P. Dale, Dec 29 2021 *)

Crossrefs

Cf. A014574.

Sequence in context: A023644 A319672 A355233 * A034923 A013022 A012908

Adjacent sequences: A145384 A145385 A145386 * A145388 A145389 A145390

Keyword

base,easy,nonn

Author

Giovanni Teofilatto, Oct 10 2008

Extensions

198 inserted by R. J. Mathar, Nov 18 2008

Status

approved