A111440 Squares of the form semiprime(n) + prime(n).

9, 25, 64, 81, 400, 576, 1024, 1296, 2304, 2704, 4096, 7225, 7744, 10816, 14884, 15376, 19044, 20736, 22500, 25600, 26244, 28900, 33124, 35344, 39601, 41616, 46656, 47961, 48400, 52900, 55225, 89401, 91204, 96100, 99856, 114921, 136900

Offset

1,1

Links

Table of n, a(n) for n=1..37.

Example

The first 3 semiprimes are {4,6,9} and the first 3 primes are {2,3,5}. The second term in each are {6,3} whose sum is 9, a square. - Robert G. Wilson v

Mathematica

sp = Select[ Range[10^5], Plus @@ Last /@ FactorInteger@ # == 2 &]; s = Select[ Range@Length@sp, IntegerQ[ Sqrt[sp[[ # ]] + Prime@# ]] &]; sp[[s]] + Prime[s]; (* Robert G. Wilson v *)

Crossrefs

Sequence in context: A147353 A049740 A147405 * A077118 A242116 A209530

Adjacent sequences: A111437 A111438 A111439 * A111441 A111442 A111443

Keyword

nonn

Author

Giovanni Teofilatto, Nov 14 2005

Extensions

More terms from Robert G. Wilson v, Nov 18 2005

Status

approved