function nanmeanors( N, x, stride, offset ) {
	var sum;
	var ix;
	var v;
	var n;
	var i;

	if ( N <= 0 ) {
		return NaN;
	}
	if ( N === 1 || stride === 0 ) {
		return x[ offset ];
	}
	ix = offset;
	sum = 0.0;
	n = 0;
	for ( i = 0; i < N; i++ ) {
		v = x[ ix ];
		if ( v === v ) {
			sum += v;
			n += 1;
		}
		ix += stride;
	}
	if ( n === 0 ) {
		return NaN;
	}
	return sum / n;
}
Computes the arithmetic mean of a strided array, ignoring `NaN` values and using ordinary recursive summation.

@param {PositiveInteger} N - number of indexed elements
@param {NumericArray} x - input array
@param {integer} stride - stride length
@param {NonNegativeInteger} offset - starting index
@returns {number} arithmetic mean

@example
var floor = require( '@stdlib/math/base/special/floor' );

var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, NaN ];
var N = floor( x.length / 2 );

var v = nanmeanors( N, x, 2, 1 );
// returns 1.25