A085803 Semiprimes whose digits squared sum to a semiprime.

15, 34, 35, 51, 57, 74, 91, 95, 121, 122, 123, 129, 134, 142, 143, 155, 161, 169, 183, 209, 213, 214, 218, 219, 221, 235, 237, 247, 253, 265, 274, 291, 299, 301, 305, 314, 319, 321, 323, 326, 327, 329, 334, 341, 361, 362, 381, 382, 391, 394, 395, 403, 407

Offset

1,1

Links

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

Mathematica

Select[Range[500], PrimeOmega[#]==PrimeOmega[Total[IntegerDigits[#]^2]] == 2&] (* Harvey P. Dale, Oct 03 2012 *)

Prog

(PARI) isok(k)={bigomega(k)==2 && bigomega(norml2(digits(k)))==2} \\ Andrew Howroyd, Sep 18 2024

Crossrefs

Intersection of A001358 and A217907.

Sequence in context: A242243 A219855 A270072 * A168573 A139578 A345733

Adjacent sequences: A085800 A085801 A085802 * A085804 A085805 A085806

Keyword

base,nonn

Author

Jason Earls, Jul 24 2003

Extensions

Offset changed by Andrew Howroyd, Sep 18 2024

Status

approved